 #1
GiantGoose
 2
 0
 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 ms1
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 ms1
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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