Physics Answers

  A  cylindrical gas tank 1 m long, inside diameter of 20 cm, is evacuated and then filled with carbon dioxide gas at 25°C. To what pressure should it be charged if there should be 1.2 kg of carbon dioxide?

If a 5-kg object experiences a 10-N force for a duration of 0.10-second, then what is the momentum change of the object?

6.5 kg chunk of ice at -12⁰C is placed in a 0.22 kg of water at 22⁰C. Ignore any heat flow with the surroundings, including the container, assume the final mixture is ice. Determine the following; 

heat lost or gained by water    

1. Block 1 of mass m1 = 2 kg is placed on block 2 of mass m2 = 3 kg which is then placed on

a table. A string connecting block 2 to a hanging mass M passes over a pulley attached to one

end of the table, as shown in Fig. 1. The mass and friction of the pulley are negligible. The

coefficients of friction between block 1 and block 2 are /1s = 0.2, M1k = 0.1 and between block

2 and the tabletop are 42s = 0.3, Mzk = 0.15.

(a) Draw the complete free body diagram of the system and determine the largest

value of M for which the blocks can remain at rest.

(b)Now suppose that M

= 2.5 kg which is large enough so that the hanging block

descends and block 1 slips on block 2. Draw the complete free body diagram of the system and

determine each of the followings.

I. The magnitude a of the acceleration of block 1

it. The magnitude ay of the acceleration of block 2

Why do helicopters always have a set of two blades?

In tearing a plastic bag from a roll, it is easier to do by a quick jerk. Why?

When two cars collide, the forces they received are equal but opposite. What about their acceleration?

If you hit somebody from behind, his head seems to snap backward. Why?

A wire made of copper is found to have a change in resistance of 17% after its temperature change. If the resistance of this wire was 8.66 Ω at 20 ⁰C, and the resistivity after the change in temperature is found to have decreased, determine the following: 

the final temperature of the wire after the change in temperature.                                                 

Select one:

 -22.5 ⁰C

 22.5 ⁰C 

 45 ⁰C

 -5 ⁰C

The velocity along a stream line passing through the origin is given by v=2V=2√x^2+y^2 what is the velocity and acceleration at (4;3)