A ball of mass 5.0kg hits a smooth vertical wall normally with a speed of 2ms\(^{-1}\). Determine the magnitude of the resulting impulse
20.0kgms\(^{-1}\)
10.0kgms\(^{-1}\)
5.0kgms\(^{-1}\)
2.5kgms\(^{-1}\)
Explanation
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Discussions (15)
@bestmvh....ur wrong theirs no recoil recall that momentum and impulse r the same and formula for momentum is mv...the question did not specify it bounced back or went in the opposite direction....so myschool is right
Impulse is defined as the change in momentum of an object when the object is acted upon by a force for an interval of time. In this case, the ball hits the wall and comes to a stop, so the change in momentum is equal to the initial momentum of the ball.
The initial momentum of the ball can be calculated using the formula:
p=mv
where
m is the mass of the ball, and
v is the velocity of the ball.
Substituting the given values:
p=5.0kg×2m/s=10.0kg m/s
However, because the ball hits the wall and rebounds in the opposite direction with the same speed, the total change in momentum (or the impulse) is twice this amount:
Impulse=2×10.0kg m/s=20.0kg m/s
So, the correct answer is A. 20.0kgms−1.
MySchool the answer you gave is not correct.
Impulse is equal to the change in momentum. a body hitting a smooth vertical wall normally,so we can assume perpendicularly, we can say it rebound with the same speed but in the opposite direction, as this is perfectly elastic collision. I = Ft =∆P = mv - mu = m(v-u)
Initial velocity is 2ms-¹ while final velocity is -2ms-¹ because it rebound with the same velocity but in opposite direction
I = 5(-2-2) = 5 × -4 = -20Ns or kgms-¹ = 20Ns or kgms-¹
MySchool please do so to correct it
The anwer is A
Since it is a ball, it must bounce back.
To calculate the impulse, we use the
ft = m(v-u)
Initial velocity, (towards the wall)
The wall is smooth and vertical, so assume an elastic collision (unless stated otherwise), meaning the ball bounces back with the same speed but opposite direction:
The magnitude of impulse is = 20kgms-1
wrong explanation!
I = m(u - v)
I = 5[2 -(-2)]...... (recoil velocity)
I = 5 × 4 = 20kgms-1
