SECTION A MECHANICS QUESTIONS

Question 1

Power can be defined as 
(A) force x distance moved
(B) force/time
(C) work done/time
(D) work done x time

Answer 1

(D) work done x time

Question 2

The measurement of the external diameter of a measuring cylinder is MOST accurately done by using a 
(A) metre rule 
(B) tape measure
(C) length of string
(D) pair of vernier calipers

Answer 2

(D) pair of vernier calipers

Question 3

A sprinter of mass 55 kg was running a 100 m race. Her velocity was measured at different intervals of a 11.0 s period. The results are recorded in Table 1.

Define the term ‘velocity’.
Acceleration is defined as the rate of change of

Using the grid provided, plot a graph of velocity, v/ms–1 against time, t/s.

Determine the slope of the graph over the first 7.0 s of the race.

State the physical quantity relating to the motion of the sprinter which the slope of the graph represents.

Describe the sprinter’s motion from 8 s to 10 s.

Calculate the resultant force acting on the sprinter after 7.0 s.

Answer 3

Velocity is the the displacement of an object per unit time.

Acceleration is defined as the rate of change of velocity per unit time.

velocity on y-axis
time on x-axis

1. Draw triangle
2. Derive units

acceleration (because m/s^2 is the unit for acceleration)

Between 8 s to 10 s the sprinter is moving with a constant velocity of 10 m/s

F = ma