A 85kg boy and a 100kg girl, both wearing skates, face each other at rest on a skating rink. The boy pushes the girl, sending her eastward with a speed of 4m/s. Calculate the velocity of the boy. (neglect friction)
If you'd be so kind as to assist me, please show how you got the answer clearly.
THANKYOU!!!! <3
If you'd be so kind as to assist me, please show how you got the answer clearly.
THANKYOU!!!! <3
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A 85kg boy and a 100kg girl, both wearing skates, face each other at rest on a skating rink. The boy pushes the girl, sending her eastward with a speed of 4m/s. Calculate the velocity of the boy. (neglect friction)
This is conservation of momentum problem!
Momentum = mass * velocity
Momentum of boy and girl before the push = 0
After the push, momentum of boy = 85 * v
After the push, momentum of girl = 100 * 4 = 400
Total momentum after push = momentum before push
85 * v + 400 = 0
85 * v = -400
v = -4.7 m/s
The negative sign means the boy is moving in the opposite direction of the girl!
This is conservation of momentum problem!
Momentum = mass * velocity
Momentum of boy and girl before the push = 0
After the push, momentum of boy = 85 * v
After the push, momentum of girl = 100 * 4 = 400
Total momentum after push = momentum before push
85 * v + 400 = 0
85 * v = -400
v = -4.7 m/s
The negative sign means the boy is moving in the opposite direction of the girl!
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M(g)V(g)=M(b)V(b).
so V(b)=100*4/85
so V(b)=100*4/85
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It's the same as the girls which is 4m/s due to Newton's 3rd law since there is no friction.