Author Question: In a certain one-lane road there are no entrances or exits. As the road passes through open country ... (Read 137 times)

cookcarl · **on:** Jul 29, 2018

In a certain one-lane road there are no entrances or exits. As the road passes through open country and populated areas, the speed limit changes. Assume that cars travel at the posted speed limit.

In the open road, where the speed limit is 55 mph, the cars are spaced so there are 51 cars per mile. If the flow of cars is steady, how many cars per mile are there in a stretch of road where the speed limit is 40 mph? A) 56 cars/mile
B) 60 cars/mile
C) 66 cars/mile
D) 70 cars/mile
E) 76 cars/mile

Question 2

A hoop with a mass of 2.75 kg is rolling without slipping along a horizontal surface with a speed of 4.50 m/s when it starts down a ramp that makes an angle of 25.0 with the horizontal.

What is the rotational kinetic energy of the hoop after it has rolled 3.00 m down the ramp? A) 34.2 J
B) 22.4 J
C) 44.9 J
D) 62.0 J
E) This question cannot be answered without knowing the radius of the hoop.