Question

a ball of mass 20gm is initially moving with a velocity of 100m/s. on applying a constant force on the ball for 0.5s it acquires a velocity of 150m/s. calculate the following:
(I) initial momentum of the ball
(ii) Final momentum of the ball
(iii) rate of change of momentum
(iv) acceleration of the ball
(v) magnitude of the force applied

Help me and get 12 points. Answer me fast. Emergency
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Answer 1

Given :

• m = 20 g = 20/1000 kg = 0.02 kg
• u = 100 m/s
• v = 150 m/s
• t = 0.5 s

To Find :

• Initial momentum of ball
• Final momentum of ball
• Rate of change of momentum
• Acceleration of ball
• Magnitude of force

Solution -

Initial momentum of ball

Initial momentum = mu = 0.02 kg × 100 m/s

Initial momentum = 2 kg m/s

Final momentum of ball

Final momentum = mv = 0.02 kg × 150 m/s

Final momentum = 3 kg m/s

Rate of change of momentum

Change in momentum = mv - mu = (3 - 2) kg m/s

Change in momentum = 1 kg m/s

Acceleration of ball

Acceleration = (v - u)/t = (150 - 100)/0.5

Acceleration = (50 × 10)/5

Acceleration = 100 m/s²

Magnitude of force

Force = ma = 0.02 kg × 100 m/s²

Force = 2 N