Efficiency of an inclined plane and collisions
Answers are for parents and teachers.
1
P = 8 N, h = 0.25 m, F = 4 N, l = 1 m. What is the useful work (J)? (P·h)
2
2
In that experiment what is the efficiency in per cent?
50
3
A 3 kg ball at 5 m/s hits a 2 kg ball at rest and sticks. What is the common speed (m/s)?
3
4
A 1 kg ball at 8 m/s hits a 3 kg ball at rest elastically. What is the first ball’s speed afterwards in magnitude (m/s)?
4
5
Why do crumple zones protect passengers in a car collision? Link with momentum and energy.
Deformation lengthens the impact time, which lowers the force, and turns much of the kinetic energy into internal energy.