A ball of mass 0.5 kg moving with a velocity of 2 metre per second strikes a wall normally and bounces back with same speed.I f
the time of contact between the ball and the wall is 1 millisecond the average force exerted by the wall on the ball
shivaji6:
0.2 5kg
Answers
Answered by
12
I think the answer is 2000N
And hence the amount of energy exerted by the wall is zero(as the ball still moves with the same speed)
According to Newton's Second Law of Motion- The force acting on a body is the rate of change of momentum of the body.. Mathematically F= m(v-u) /Δt where, v= final velocity of object u= initial velocity Δt=time taken in the change and m is mass of the object as you know.. Also according to your question your question the ball bounces back I. e. if we consider it's v positive then u will be negative because of opposite directions..
Putting v= 2m/s and u= -2m/s in the formula with other values we get the required force
If the wall exerts 200N as you said... How can the ball still move the same speed?
Listen according to this question we have assumed that the collision bw the wall and the ball Is elastic I. e. the momentum and the kinetic energy of the ball is conserved..
We have assumed.. That's your answer you don't have to look practically because that thing is not possible
Also U must have known according to 3rd law of Newtonian Mechanics that the force pairs acting on a system does not necessarily cancel each other.. Only their effects are different according to their masses
Then why is the ball still moving at the same speed?
Because it's kinetic energy is conserved.. It's KE is same before and after its collision with the wall
What about the 200N?
Answered by
14
mass of ball 0.5 kg
velocity 0.2 kg
when the ball bounces with the same velocity mass will remain constant but direction must be reversed
therefore
force will be ma
or you would say m∆v/t
therefore change in momentum will be ∆p that is mv-(-mv)
that is 2mv
hence change in momentum will be 2×0.5×2
2 kg-m/s
now we have to find average force
that will be
Fav = total force or impulse or change in momentum/ total time
2/ 1 × 10-³ N (because 1 millisec is 10-³ sec)
hence your answer is 2000 N
hope it helped you
mark me brainliest
Similar questions