Questions posted in Physics

Rosita weighed 50 n when she traveled to mars, a planet with an acceleration due to gravity that is about one-third as large as earthâs acceleration due to gravity. about how much does rosita weigh on earth?

About 150 n I believe is correct. Please rate brainliest and everyone thank ;)

ANSWERED AT 18/11/2019 - 03:38 AM


QUESTION POSTED AT 18/11/2019 - 03:38 AM

A new roller coaster contains a loop-the-loop in which the car and rider are completely upside down if the radius of the loop is

Sorry, but the question seems to be incomplete.

ANSWERED AT 18/11/2019 - 03:33 AM


QUESTION POSTED AT 18/11/2019 - 03:33 AM

Convection in the atmosphere is the process whereby air masses rise and fall, distributing heat and moisture over the planet. a. True b. False

I believe the correct answer would be true. Convection in the atmosphere is the process wherein the air masses rise and fall which results to the distribution of heat and moisture over the planet. It refers mainly to the atmospheric movements in the vertical direction so the rise and the fall. It is the result of the temperature difference of the lower air and the higher altitude air which results to the difference of the density of these air. In order to maintain equilibrium,  these masses of air would rise and fall accordingly depending on their differences affecting the average temperature of the Earth.

ANSWERED AT 18/11/2019 - 03:29 AM


QUESTION POSTED AT 18/11/2019 - 03:29 AM

Suppose that a constant force is applied to an object. newton's second law of motion states that the acceleration of the object varies inversely with its mass. a certain force acting upon an object with mass 2 kg produces an acceleration of 38 /ms2 . if the same force acts upon another object whose mass is 19 kg , what would this object's acceleration be?

Newton’s second law states that force is the product of mass and acceleration. This is expressed mathematically as:

F = m * a

Where F = force, m = mass, a = acceleration

Since in the given problem, the force is constant or same force is acting upon two objects. Therefore we can simply equate the expression m * a of the 2 objects.

m1 * a1 = m2 * a2

Where m1 = 2 kg, a1 = 38 m/s^2, m2 = 19 kg. Therefore finding for a2:

2 kg * 38 m/s^2 = 19 kg * a2

a2 = 4 m/s^2     (ANSWER)

ANSWERED AT 18/11/2019 - 03:29 AM


QUESTION POSTED AT 18/11/2019 - 03:29 AM

The position function x (6.0 m) cos[(3p rad/s)t p/3 rad]gives the simple harmonic motionof a body. at t 2.0 s, what are the(a) displacement, (b) velocity, (c)acceleration, and (d) phase of the motion? also, what are the (e)frequency and (f) period of the motion?

The correct formula for this simple harmonic motion is:

x = (6.0) cos [ (3 pi) t + pi/3 ] 

 

A. Calculating for displacement x at t = 2:

x =6.0 cos (19/3 pi)
x = 6 (0.5)

x = 3 m

 

B. Velocity is equivalent to the 1st derivative of the equation. v = dx / dt

 Velocity v = dx/dt = -18 pi sin (3pi t + pi/3) 

v = - 18 pi sin (6pi + pi/3)

v = 49.0 m/s

 

C. Acceleration is the 2nd derivative or the 1st derivative of velocity dv / dt
Acceleration a = dv/dt = -54 pi^2 cos(3pi t + pi/3) 

a = -54 pi^2 cos(3pi * 2 + pi/3)

a = 386.34 m/s^2

D. Phase = pi/3 

E. frequency f= 3pi/2pi = 1.5Hz 


F. period = 1/f = 1/1.5 = .6667sec 

ANSWERED AT 18/11/2019 - 03:16 AM


QUESTION POSTED AT 18/11/2019 - 03:16 AM

What happens to an electric current when it flows through an object with resistance?

When a current passes through an object with finite resistance some of it dissipates giving out heat.Hope this helps!!:-)

ANSWERED AT 18/11/2019 - 03:08 AM


QUESTION POSTED AT 18/11/2019 - 03:08 AM

How do the components of a vector transform under a translation of coordinates?

Vectors are invariant under translation. This means that they are unaffected or unchanged even if the coordinates are translated. So while the coordinates of two points are changed or moved during translation, the distance between the two points does not change. The best way to picture this out is using real life scenario. For example, you and I are at rest relative to each other but sitting on a plane at different locations, then we will have a fixed distance. Now the plane flies and its overall location is changed, similarly our individual coordinates also change but the distance between us will remain the same.

ANSWERED AT 18/11/2019 - 03:07 AM


QUESTION POSTED AT 18/11/2019 - 03:07 AM

If the pressure on a gas sample is tripled and the absolute temperature is quadrupled, by what factor will the volume of the sample change?

Let as assume the simplest calculation by assuming that the gas is ideal. Therefore, the equation would be PV=nRT, where P is pressure, V is volume, n is the amount of moles of gas, R is the gas constant and T is the absolute pressure. Let us further assume that the amount of gas, n, is constant before and after the change. With that being said, the volume is equal to

V = nRT/P = kT/P

The term k is lumped as a constant because they are the same before and after the change. Next, we find the ratio of V1 (before the change) and V2 (after the change).

V2/V1 = (k*4T/3P)/(kT/P)

Cancelling out like terms would yield

V2/V1 = 4/3

Therefore, the volume after the change is 4/3 of the original volume. This means that the volume increased by (4/3-1 = 1/3 or 33%) 33% after the change of conditions.

ANSWERED AT 18/11/2019 - 02:55 AM


QUESTION POSTED AT 18/11/2019 - 02:55 AM

An air core solenoid with 68 turns is 8 cm long and has a diameter of 1.2 cm. how much energy is stored in its magnetic field when it carries a current of 0.77a?

To determine the energy stored in the magnetic field, use the formula: E = ½ LI2 where E is the energy stored, L is the inductance (units: Henry), and I is the current (units: Ampere).

Correspondingly, L = (µN2A)/l, where, µ = permeability of medium (in this case, air), N = no. of turns, A = cross-sectional area, and l = length. Given: N = 68 turns, l = 8 cm, d = 1.2 cm, and I = 0.77 A, other necessary variables are A = 1.13 cm2 and µair = 1.2566 x 10-6 H/m. Applying the formula and checking that the units agree with each other, the final answer is 2.4352 x 10-6 J.

ANSWERED AT 18/11/2019 - 02:55 AM


QUESTION POSTED AT 18/11/2019 - 02:55 AM

What effect does heating a solid to a high temperature have on its crystal lattice?

You should know from basic science that the difference in the three phases of matter is the arrangement of their molecules. Solids have compact molecules. Because of this, it is relatively more organized such that it is made up simple, repeating blocks of unit cells. This is called the crystal lattice. When the solid is heated, the kinetic energy of the system increases, thereby increasing frequency of collisions. But since the solid's atoms are compact, they merely vibrate. When the energy gets too high so that phase transformation can be achieved, the space inside the crystal lattice expands and the atoms move farther away from each other. Then, they could turn into a liquid of gaseous phase.

ANSWERED AT 18/11/2019 - 02:55 AM


QUESTION POSTED AT 18/11/2019 - 02:55 AM

If 60 lbs of force must be applied to the valve for it to open, how much upward force must push rod X apply for the valve to open?

I think is 15 or 20 im not sure

ANSWERED AT 18/11/2019 - 02:51 AM


QUESTION POSTED AT 18/11/2019 - 02:51 AM

During a breath, the average human lung expands by about 0.50 l. part a if this expansion occurs against an external pressure of 1.0 atm, how much work (in j) is done during the expansion?

Work, in thermodynamics, is the amount of energy that is transferred from one system to another system without transfer of entropy. It is equal to the external pressure multiplied by the change in volume of the system. It is expressed as follows:

W = PdV

Integrating and assuming that P is not affected by changes in V or it is constant, then we will have:

W = P (V2 - V1)

Substituting the given values:
P = 1.0 atm = 101325 Pa
(V2 - V1) = 0.50 L = 
W = 101325 N/m^3 ( 0.50) (1/1000) m^3
W = 50.66 N-m or 50.66 J

So, in the expansion process about 50.66 J of work is being done.

ANSWERED AT 18/11/2019 - 02:45 AM


QUESTION POSTED AT 18/11/2019 - 02:45 AM

A one-family dwelling contains an electric range rated at 25 kw. what is the neutral load demand for this range

right answer 13.2kW. or 13200VA,

after 12kW, 5% times one additional kW. 13kWx5%=0.65

220.55 table 1 appliance column C 8kW

8x1.65=13.2kW or 13200VA


ANSWERED AT 18/11/2019 - 02:44 AM


QUESTION POSTED AT 18/11/2019 - 02:44 AM

If you are in a rear-wheel skid, you must release your brakes and turn your steering wheel __________ a. into the direction of the skid. b. opposite direction of the skid. c. straight.

I think the correct answer would be A. If you are in a rear-wheel skid, you must release your brakes and turn your steering wheel into the direction of the skid. A skid in vehicles is a situation wherein one or more wheels are slipping in relation to the road and affecting the whole handling of the vehicle. To do a rear wheel skid, you should be releasing the break with caution and move or steer the wheel into the direction you would want to move. 

ANSWERED AT 18/11/2019 - 02:40 AM


QUESTION POSTED AT 18/11/2019 - 02:40 AM

A boat is floating in a small pond. the boat then sinks so that it is completely submerged. what happens to the level of the pond?

A boat is floating in a small pond. the boat then sinks so that it is completely submerged. what happens to the level of the pond?
It increases!

ANSWERED AT 18/11/2019 - 02:37 AM


QUESTION POSTED AT 18/11/2019 - 02:37 AM

A landscaper is making a retaining wall to shore up the side of a hill. to ensure against collapse, the wall should make an angle 75° with the ground. how far from the base of the hill is the base of a 15-foot slanted wall?

Refer to the diagram shown below.

Let x  =  distance of the base of the ladder from the base of the hill.

By definition,
sin(75°) = x/15
x = 75*cos(75°) = 3.882 ft

Answer:
The distance between the base of the hill and the base of the ladder is 3.9 ft (nearest tenth)

ANSWERED AT 18/11/2019 - 02:36 AM


QUESTION POSTED AT 18/11/2019 - 02:36 AM

A bird flew16 km west in 5 hours, then flew 20 km east in 6 hours. what was the birdâs velocity?

Solve for Speed: 16+20=36 km in 11 hrs
Answer: speed = 3.27273 kilometers per hour

To solve for speed or rate use the formula for speed, s = d/t which means speed equals distance divided by time.

speed = distance/time

ANSWERED AT 18/11/2019 - 02:32 AM


QUESTION POSTED AT 18/11/2019 - 02:32 AM

As the external magnetic field decreases, an induced current flows in the coil. what is the direction of the induced magnetic field caused by this current?

As the external magnetic field decreases, an induced current flows in the coil. The direction of the induced magnetic field would be pointing to the screen. The flux through the coil is said to decrease. In order to counter this change, the coil would generate or produce a magnetic field that is induced that would be pointing to the same direction as the external field that is flowing which is into the the screen. This is according to Lenz's law or the right hand rule. It states that an induced current in a circuit that is due to the change or motion in   magnetic field should be directed opposing to the change in the flux.

ANSWERED AT 18/11/2019 - 02:31 AM


QUESTION POSTED AT 18/11/2019 - 02:31 AM

Theories have both an explanatory and a predictive function. a. True b. False

Answer:

true

Explanation:

Theories have both an explanatory an a predictive function.

ANSWERED AT 18/11/2019 - 02:31 AM


QUESTION POSTED AT 18/11/2019 - 02:31 AM

Stars originate as large bodies of slowly rotating gas. because of gravity, these clumps of gas slowly decrease in size. the angular velocity of a star increases as it shrinks because of

Stars originate as large bodies of slowly rotating gas. because of gravity, these clumps of gas slowly decrease in size. the angular velocity of a star increases as it shrinks because of the angular momentum conservation.

This is because in a rotary system with decreasing diameter, the angular momentum should be conserved (as long as the net torque is zero) based on physics conservation laws

ANSWERED AT 18/11/2019 - 02:23 AM


QUESTION POSTED AT 18/11/2019 - 02:23 AM

A basketball is tossed up into the air, falls freely, and bounces from the wooden floor. from the moment after the player releases it until the ball reaches the top of its bounce, what is the smallest system for which momentum is conserved? the ball plus player the ball momentum is not conserved the ball plus earth

I would say the smallest system for which the momentum will be preserved will be the ball plus the earth though in this case it would be the wooden floor since the last thing it does is bounce from the floor up in the air so that is the last system,

ANSWERED AT 18/11/2019 - 02:23 AM


QUESTION POSTED AT 18/11/2019 - 02:23 AM

At what condition the screw guage does not have zero error?

Let me help you!
You will arrive with a zero error if: The thimble is above the datum line. Else, the result will always be positive. I honestly forgot the reasoning behind why that is but there is a formula for that and you can use it to prove what I just shared. Better luck! 

ANSWERED AT 18/11/2019 - 02:19 AM


QUESTION POSTED AT 18/11/2019 - 02:19 AM

The distance, in feet, a moving object has traveled after t seconds is given by 2t/(4 + t). find the acceleration of the object after 5 seconds. (round your answer to three decimal places.)

Hi! Let me help you!
a = (Vf - Vi)/t ; where distance d = [2(t)]/(4+t), t = 5secs, and Vi = 0 
a = [(2t)/(4+t)]/t <---- working equation
a = {[2(5)]/9}/5 <---- cancel 5
a = 2/9 ft/s^2 <---- Answer

ANSWERED AT 18/11/2019 - 02:18 AM


QUESTION POSTED AT 18/11/2019 - 02:18 AM

A 1.0 kg football is given an initial velocity at ground level of 20.0 m/s [37 above horizontal]. It gets blocked just after reaching a height of 3.0 m. (a) What is the velocity of the football when it first reaches a height of 3.0 m above the level ground? (b) What horizontal distance has the ball travelled when it first reaches a height of 3.0 m above ground?

Refer to the diagram shown below.

Neglect air resistance.
The horizontal component of the launch velocity is
 (20 m/s)*cos(37°) = 15.973 m/s
The vertical component of the launch velocity is
 (20 m/s)*sin(37°) = 12.036 m/s

The acceleration due to gravity is g =9.8 m/s².
The time, t s, for the ball to reach a height of 3 m is given by 
(12.036 m/s)*(t s) - (1/2)*(9.8 m/s²)*(t s)² = (3 m)
12.036t - 4.9t² - 3 = 0
2.4543t - t² - 0.6122 = 0
t² - 2.4563t + 0.6122 = 0
Solve with the quadratic formula.
t = (1/2)[2.4563 +/- √(6.0334 - 2.4488)]
t = 2.1748 or 0.2815 s
The ball reaches a height of 3 m twice.
The first time it reaches 3 m height is 0.2815 s.

Part a.
The vertical velocity when t = 0.2815 s is
Vy  = 12.036 - 9.8*0.2815
   = 9.2773 m/s
The horizontal component of velocity is Vx = 15.973 m/s
The resultant velocity is 
√(9.2773² + 15.973² ) = 18.47 m/s
Answer:
The velocity at a height of 3.0 m  is 18.5 m/s (nearest tenth)

Part b.
The horizontal distance traveled is 
d = (15.973 m/s)*(0.2815 s) = 4.4964 m
Answer:
The horizontal distance traveled is 4.5 m (nearest tenth)

ANSWERED AT 18/11/2019 - 02:12 AM


QUESTION POSTED AT 18/11/2019 - 02:12 AM

Ben(55 kg) is standing on very slippery ice when junior(25kg) bumps into him. junior was moving at a speed of 8m/s before the collision and ben and junior embrace after the collision. find the speed of ben and junior as they move across the ice after the collision .

Define
m₁= 55 kg, mass of Ben
m₂ = 25 kg, mass of Junior

v₁ = 0, initial speed of Ben (he was stationary)
v₂ = 8 m/s, speed of Junior

Consider the motion of Ben and Junior as occurring within a closed system.
Because momentum is preserved, the initial momentum of the system is equal to the final momentum of the system.

Refer to the figure shown below.
The initial momentum is
P₁ = m₁v₁ + m₂v₂
    = (55 kg)*(0 m/) + (25 kg)*(8 m/s)
    = 200 (kg-m)/s

Let V =   the speed of Ben and Junior (in an embrace) after the collision.
The final momentum is
P₂ = (m₁ + m₂)V
    = (55+25 kg)*(V m/s)
    = 80V (kg-m)/s

Equate P₁ and P₂ to obtain
80V = 200
    V = 2.5 m/s

Answer:  2.5 m/s

ANSWERED AT 18/11/2019 - 02:04 AM


QUESTION POSTED AT 18/11/2019 - 02:04 AM

D is at rest at the top of a 2 m high slope. The sled has a mass of 45 kg. The sled's potential energy is J?

D is at rest at the top of a 2 m high slope. The sled has a mass of 45 kg. The sled's potential energy is J?
Answer: The sled's potential energy is 882 Joules

ANSWERED AT 18/11/2019 - 02:04 AM


QUESTION POSTED AT 18/11/2019 - 02:04 AM

The Bay of Fundy is known for its?

The highest tides and rarest whales on earth

ANSWERED AT 18/11/2019 - 02:02 AM


QUESTION POSTED AT 18/11/2019 - 02:02 AM

Polyatomic ions bond with other ions to form ionic:

Answer;


Ionic compounds


Polyatomic ions bond with other ions to form ionic compounds.


Explanation;


-Polyatomic ions are ions which consist of more than one atom. For example, nitrate ion, NO3-, contains one nitrogen atom and three oxygen atoms.The atoms in a polyatomic ion are usually covalently bonded to one another, and therefore stay together as a single, charged unit.


-Ionic compounds are compounds made up of ions. These ions are atoms that gain or lose electrons, giving them a net positive or negative charge.Metals tend to lose electrons, so they become cations and have a net positive charge. Nonmetals tend to gain electrons, forming anions that have a net negative charge.

ANSWERED AT 18/11/2019 - 01:59 AM


QUESTION POSTED AT 18/11/2019 - 01:59 AM

It is MOST accurate to say the the body mass index (BMI) provides information about ____________. A. Body composition. B. An individual's height-weight ratio C. Cardiorespitory fitness levels D. An individual's height

It is most accurate to say that body mass index (BMI) provides information about an individual's height-weight ratio. The correct answer is B.

ANSWERED AT 18/11/2019 - 01:57 AM


QUESTION POSTED AT 18/11/2019 - 01:57 AM