A child\'s sled has rails that slide with little friction across the snow. Logan
ID: 2147354 • Letter: A
Question
A child's sled has rails that slide with little friction across the snow. Logan has an old wooden sled with heavy iron rails that has a mass of 8.0kg quite a bit for a 29kg child! Logan runs at 4.3m/s and leaps onto the stationary sled and holds on tight as it slides forward. The impact time with the sled is 0.27s .1. Immediately after Logan jumps on the sled, how fast is it moving? value+units
vf= ???
2. What was the force on the sled during the impact? value+units
F=
3. How much energy was "lost" in the impact? value+units
Delta K = .....
4.Where did this energy go?
the energy was dissipated as.....
a. gravitational potential energy
b. elastic potential energy.
c. kinetic energy
d. thermal energy
Explanation / Answer
Conservation of momentum 31 . 4.1 = (31 + 11 ) . V (sled ) V = 31 . 4.1 / 42 Force . time = change in momentum of the sled F . 0.27 = 11 . 31 . 4.1 / 42 F = 11 . 31 . 4.1 / 42 . 0.27 N Energy "lost" is (0.5 . 31 . 4.1^2 ) - ( 0.5 . 42 . ( 31 . 4.1 / 42 )^2 )