CH6. A cart full of whistles and bells rolls down a slope (ignore friction) and
ID: 1543872 • Letter: C
Question
CH6. A cart full of whistles and bells rolls down a slope (ignore friction) and impacts a spring at the base of the hill. The initial height and velocity of the car are given. a) By how much, x, does the cart compress the spring before coming to m 3.0 kg a complete stop? vo 5.0 m/s k 630 N/m b) The spring rebounds and the cart is sent back up the hill. What is the maximum height, hma, of the cart above the ground when it comes to a momentary stop? 000 c) In the absence of friction this exchange will just go on forever. But h m 1.2 m. in the real world where does the cart end up?Explanation / Answer
a)
using conservation of energy
spring potential energy due to compression = initial potential energy of cart
(0.5) k x2 = mgh
(0.5) (630) x2 = 3 x 9.8 x 1.2
x = 0.335 m
b)
using conservation of energy again
final potential energy of cart = spring potential energy due to compression
(0.5) k x2 = mgh
hmax = 1.2 m
c)
in real work , the cart will loose some energy and hence comes to a stop finally after moving several times
H7)
using conservation of energy
(0.5) (m1 + m2) Vo2 + m2 gh = (0.5) (m1 + m2) Vf2
(0.5) (8 + 5) (2.5)2 + (5) (9.8) (1.4) = (0.5) (8 + 5) Vf2
Vf = 4.1 m/s