Unlock document.
This document is partially blurred.
Unlock all pages and 1 million more documents.
Get Access
PROBLEM 13.199
A 2-kg ball B is traveling horizontally at
10 m/s when it strikes 2-kg ball A. Ball A is
initially at rest and is attached to a spring with
constant 100 N/m and an unstretched length
of 1.2 m. Knowing the coefficient of
restitution between A and B is 0.8 and friction
between all surfaces is negligible, determine
the normal force between A and the ground
when it is at the bottom of the hill.
SOLUTION
A Bn
PROBLEM 13.199 (Continued)
0.7
n
ρ
n
PROBLEM 13.199 (Continued)
Apply Newton’s second law to the ball.
PROBLEM 13.200
A 2-kg block A is pushed up against a spring compressing it a
distance x. The block is then released from rest and slides down
the
20°
incline until it strikes a 1-kg sphere B which is
suspended from a 1 m inextensible rope. The spring constant
800k=
N/m, the coefficient of friction between A and the
ground is 0.2, the distance A slides from the unstretched length
of the spring
1.5 md=
and the coefficient of restitution
between A and B is 0.8. Knowing the tension in the rope is 20 N
when
30 ,
α
= °
determine initial compression x of the spring.
SOLUTION
PROBLEM 13.200 (Continued)
PROBLEM 13.201*
The 2-lb ball at A is suspended by an inextensible cord and given an initial
horizontal velocity of v0. If l = 2 ft, xB = 0.3 ft and yB = 0.4 ft determine the
initial velocity v so that the ball will enter in the basket. Hint: use a computer
to solve the resulting set of equations.
SOLUTION
Let position 1 be at A.
10
vv=
02
PROBLEM 13.201* (Continued)
2
2
2cos30 0.3 0.50473s
5.6745sin 30
2sin 30 (5.6745cos30 )(0.50473) (16.1)(0.50473)
0.62116 ft
B
B
tt
y
°−
−= =
°
= °+ ° −
= −
PROBLEM 13.201* (Continued)
PROBLEM 13.201* (Continued)
0
PROBLEM 13.CQ1
Block A is traveling with a speed v0 on a smooth surface when the
surface suddenly becomes rough with a coefficient of friction of
m
causing the block to stop after a distance d. If block A were traveling
twice as fast, that is, at a speed 2v0, how far will it travel on the rough
surface before stopping?
(a) d/2
(b) d
(c)
d2
(d) 2d
(e) 4d
SOLUTION
2
1
PROBLEM 13.CQ2
Two small balls A and B with masses 2m and m respectively are released
from rest at a height h above the ground. Neglecting air resistance, which of
the following statements are true when the two balls hit the ground?
(a) The kinetic energy of A is the same as the kinetic energy of B.
(b) The kinetic energy of A is half the kinetic energy of B.
(c) The kinetic energy of A is twice the kinetic energy of B.
(d) The kinetic energy of A is four times the kinetic energy of B.
SOLUTION
PROBLEM 13.CQ3
Block A is released from rest and slides down the frictionless
ramp to the loop. The maximum height h of the loop is the same
as the initial height of the block. Will A make it completely
around the loop without losing contact with the track?
(a) Yes
(b) No
(c) need more information
SOLUTION
PROBLEM 13.CQ4
A large insect impacts the front windshield of a sports car traveling down a road. Which of the following
statements is true during the collision?
(a) The car exerts a greater force on the insect than the insect exerts on the car.
(b) The insect exerts a greater force on the car than the car exerts on the insect.
(c) The car exerts a force on the insect, but the insect does not exert a force on the car.
(d) The car exerts the same force on the insect as the insect exerts on the car.
(e) Neither exerts a force on the other; the insect gets smashed simply because it gets in the way of the car.
