Physics Past Questions and Answers

An object of mass 2kg moving with a velocity 3ms^-11 collides head-on with another object of mass 1kg moving in the opposite direction with a velocity of 4ms^-1. If the objects stick together after collision, calculate their common speed.

A 0.60ms^-1
B 0.67ms^-1
C 2.00ms^-1
D 3.33^-1

Question 1222:

A ball is dropped and it hits the floor at a point A. It rebounds upward to a point B. While moving from A to B its

A Kinetic energy is increasing
B Potential energy is increasing
C Potential energy is decreasing
D Kinetic energy remains constant

Question 1223:

Which of the following devices convert heat energy to electrical energy?

A Transformer
B Dynamo
C Thermocouple
D Thermostat

Question 1224:

An object of mass 0.25kg moves at a height h above the ground with a speed of 4ms^-1, if its mechanical energy at this height is 12 J, determine the value of h. [g = 10ms^-1]

A 0.8m
B 4.0m
C 4.8m
D 5.6m

Question 1225:

Which of the following equations for the efficiency of a machine is correct?

A Efficiency = \(\frac{\text{Velocity Ratio}}{\text{Mechanical Advantage}}\) x 100%
B Efficiency = \(\frac{input}{output}\) x 100%
C Efficiency = \(\frac{\text{load distance}}{\text{effort distance}}\) x 100%
D Efficiency = \(\frac{\text{Mechanical Advantage}}{\text{Velocity Ratio}}\) x 100%