Answer:
The velocity is 
Explanation:
From the question we are told that
The first distance is 
The first speed is 
The second distance is 
The second speed is 
Generally the time taken for first distance is



The time taken for second distance is



The total time is mathematically represented as

=> 
=> 
Generally the constant velocity that would let her finish at the same time is mathematically represented as

=> 
=> 
Answer:
A=0.199
Explanation:
We are given that
Mass of spring=m=450 g=
Where 1 kg=1000 g
Frequency of oscillation=
Total energy of the oscillation=0.51 J
We have to find the amplitude of oscillations.
Energy of oscillator=
Where
=Angular frequency
A=Amplitude

Using the formula



Hence, the amplitude of oscillation=A=0.199
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 