Physics Answers

a quantity of low density gas in rigid container is initially at room temperature ( 20 degrees C ) and a particular pressure P1. If the gas Is heated to a temperature of 60 degrees C, by what factor does the pressure change.

A body of mass 3kg and volume 4×10^-4m^3 is hung from balance graduated in newtons. What is the reading of the balance when the body is;

a. In air

b. Fully immersed in water

c. ⅓ immersed in water

d. Fully immersed in paraffin.(Density of water is 10^3kgn^-3 and Density of paraffin is 800kgm^-3

Dissatisfied with the performance of his heat engine in the previous example, the engineer

wishes to increase its efficiency to 25%. To accomplish this, he decided to change the

temperature of the hot reservoir while keeping the temperature of the cold reservoir constant.

What must be the temperature of the hot reservoir of the engine?

Total calories burned = ?

f he/she just sleep 5 hours, how many calories burned?

How much heat is needed to change the temperature of a 2.0 kg of block of copper from 10°C to 140°C?

in a uniform electric field near the surface of earth, a particule having a charge of -2.0*10^-9C is acted on by a downward electric force of 3.0*10^-6N,

1. What is the magnitude and direction of the electric force exerted on a proton placed in the field?

2. What is the gravitational force on the proton?

3. What is the ratio of the electric force to the gravitational force in the case

in a uniform electric field near the surface of earth, a particule having a charge of -2.0*10^-9C is acted on by a downward electric force of 3.0*10^-6N, what is the magnitude of the electric field

3. James (26 kg) sits on a wheeled office chair (16 kg) holding a fire extinguisher (18 kg when empty). He points the discharge horn to the right and ejects 9 kg of carbon dioxide at 20 m/s. What is his speed and direction after the fire extinguisher is emptied (assuming friction is negligible)?

A football is kicked with a velocity of 20 m/s at an angle of 37° with the horizontal. Determine:

a. Maximum height reached by the ball

b. Time of flight

c. Horizontal distance traveled

An astronaut on the Moon dropped a tool from his space vehicle which is 5m from the ground. How long would it take for the tool to reach the ground?