For an investigation, a student measures the speed of a cart as it rolls down a ramp. The student then records data in the table shown above. Which of these best explains the student’s data? A.
The speed of the cart decreases as the cart rolls down the ramp because of friction between the cart and the ramp.

B.
The speed of the cart increases as the cart rolls down the ramp because the force acting on the cart is greater than the force of gravity.

C.
The speed of the cart increases as the cart rolls down the ramp because the forces acting on the cart are unbalanced.

D.
The speed of the cart decreases as the cart rolls down the ramp because the forces acting on the cart are balanced.

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?