The picture shows a rollercoaster car as it is about to descend a high hill. The car's speed at the top (point A) is 2 m/s, and the crest is 44 m high, as measured from the ground. a) Neglecting friction, what is the speed of the car at the bottom of the hill (point B), 5 m above ground? b) Suppose that the work done by friction reduces the energy by 5% during the descent. Compute the new speed at the bottom of the ride. Take the mass of the car and passengers combined to be 480 kg.

Answer quickly (15 points) a comet is approaching earth. describe earth’s gravitational pull as the comet gets closer to it. a. remain constant b. increase c. decrease d. reversed

Afixed electric space heater wired by a cable with an ampacity of 30 a should draw a maximum current of a. 30 a. b. 24 a. c. 15 a. d. 27 a.

Amass m = 74 kg slides on a frictionless track that has a drop, followed by a loop-the-loop with radius r = 18.4 m and finally a flat straight section at the same height as the center of the loop (18.4 m off the ground). since the mass would not make it around the loop if released from the height of the top of the loop (do you know why? ) it must be released above the top of the loop-the-loop height. (assume the mass never leaves the smooth track at any point on its path.) 1. what is the minimum speed the block must have at the top of the loop to make it around the loop-the-loop without leaving the track? 2. what height above the ground must the mass begin to make it around the loop-the-loop? 3. if the mass has just enough speed to make it around the loop without leaving the track, what will its speed be at the bottom of the loop? 4. if the mass has just enough speed to make it around the loop without leaving the track, what is its speed at the final flat level (18.4 m off the ground)? 5. now a spring with spring constant k = 15600 n/m is used on the final flat surface to stop the mass. how far does the spring compress?