4. Table 2.4 shows how the displacement of a runner changed
during a sprint race. Draw a displacement–time graph to show
this data, and use it to deduce the runner’s speed in the middle
of the race.
Table 2.4 Data for a sprinter during a race
Displacement
(m)
0 4 10 20 50 80 105
Time (s) 1 2 3 6 9 12
Answer:
(a) Magnetic moment will be 
(b) Torque will be 
Explanation:
We have given dimension of the rectangular 5.4 cm × 8.5 cm
So area of the rectangular coil 
Current is given as 
Number of turns N = 25
(A) We know that magnetic moment is given by 
(b) Magnetic field is given as B = 0.350 T
We know that torque is given by 
Answer:
Explanation:
Given
Radius of cylinder r=0.1 m
Length L=0.2 in.
Moment of inertia I=0.020 kg-m^2
Force F=1 N
We Know Torque is given by

where 


Answer:
230 m/s northeast, 1.8 m/s up
Explanation:
204 kilometres = 204000 metres
15.0 minutes = 900 seconds
Velocity = Distance / Time
= 204000 / 900
= 230 m/s northeast (to 2 sf.)
1.6km = 1600 metres
Velocity = 1600 / 900
= 1.8 m/s up (to 2 sf.)