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Physics - calculate change in momentum

A ball of mass 1.5kg travelling at 3.6m/s in the + x-direction hits a wall and rebounds with the same speed. What is the change in its momentum?

Posted in Physics, asked by PATRICIA, 6 years ago. 1854 hits.

0

Given:

m= 1.5 kg 
v1 = 3.6 m/s
v2 = -3.6 m/s (rebound)


p = mv 
Δp = mΔv = m(vf-vi)

Δv = ((-3.6)-3.6)

     = -7.2

 The work was mostly correct, but change in velocity is (final velocity - initial velocity), so the change in velocity is -7.2 m/s, not +7.2 m/s. 

therefore,

Δp = 1.5 x -7.2

     = -10.8 kgm/s

 Since the velocity, which has direction (ie negative/positive), is negative, then the change in momentum is also negative.

Nelson Kim
Nelson Kim - 6 years ago
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-1

Given:
m= 1.5 kg
v1 = 3.6 m/s
v2 = -3.6 m/s (rebound)



p = mv
Δp = mΔv

Δv = (3.6-(-3.6))

     = 7.2

 

therefore,

Δp = 1.5 x 7.2

     = 10.8 kgm/s

Gurudas Kadam
Gurudas Kadam - 6 years ago
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