- #1

GiantGoose

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- Homework Statement
- See attached.

Graph shows variation of force experienced by ball of 250g mass when thrown against a wall. Comes to rest at point Q.

a) Did the ball collide elastically or inelastically with the wall? Justify.

b) Calculate the speed of the ball at point R

c) What was the magnitude of the average acceleration of the ball during the interval PQ?

- Relevant Equations
- F=ma

change in momentum = final - initial

change in momentum = force x time

a) Assuming it is inelastic as it is accelerating and therefore kinetic energy is not conserved? Intuitively this doesn't feel right...

b) change in momentum = p initial - p final = force x time

p initial = 0 as at rest

p final = 0.25 x v2

force x time = area under graph = 0.1

therefore 0.25 x v2 = 0.1

v2 = 0.4 ms-1

c) After google searching I have discovered that acceleration is the area under the graph of a f against t graph, but I am certain I have not been taught this. Is there are more intuitive way to figure this out?

Many thanks!

b) change in momentum = p initial - p final = force x time

p initial = 0 as at rest

p final = 0.25 x v2

force x time = area under graph = 0.1

therefore 0.25 x v2 = 0.1

v2 = 0.4 ms-1

c) After google searching I have discovered that acceleration is the area under the graph of a f against t graph, but I am certain I have not been taught this. Is there are more intuitive way to figure this out?

Many thanks!

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