Question

Some kids who watched the show jackass too many times strap a big rocket to a sled on a large horizontal parking lot covered in ice with a coefficient of kinetic friction, μ_k = 0.14. The mass of the sled while occupied is 227.5kg, where we ignore the mass of the rocket and propellant. Over the course of 18s and starting from rest, the sled has a velocity of 21.3m/s. (a) Assuming we rotate our coordinate system so that they are moving along an axis and in a positive direction, what is the average acceleration of the sled in the horizontal direction? (b) What is the average force that the rocket exerts on the sled in the horizontal direction? After 24s and still moving with constant acceleration (assuming the average acceleration is constant), the rocket runs out of fuel. Then they move with constant velocity in an especially slippery part of the lot (negligible friction in the location just after the rocket runs out of fuel). (c) At what speed are the occupants moving after the rocket ran out of fuel? A wall directly in the path of the sled that is now moving at a constant velocity. The sled is completely stopped and the time of collision is 0.16s. (d) What is the magnitude of the average force that the wall exerts on the sled full of children?

Answer 1