1. A pole is held vertically by attaching wires at a height of 13.4 m above the ground. The other end of each wire is anchored in the ground at a distance of 9.54 m from the base of the pole. The pole makes a right angle with the ground. What is the length of each wire?
2. A bug crawls 2.25 m along the base of a wall. Upon reaching a
corner, the bug's direction of travel changes from south to west.
The bug then crawls 3.15 m before stopping. What is the magnitude
of the bug's displacement?
3. Carl Lewis set a world record for the 100.0-m run with a time of
9.86 s. If, after reaching the finish line, Mr. Lewis walked
directly back to his starting point in 90.9 s, what is the
magnitude of his average velocity for the 200.0 m?
4. Water drips from rest from a leaf that is 15 meters above the
ground. Neglecting air resistance, what is the speed of each water
drop when it hits the ground?
5. The wheels of an automobile are locked as it slides to a stop
from an initial speed of 30.0 m/s. If the coefficient of kinetic
friction is 0.600 and the road is horizontal, approximately how
long does it take the car to stop?
6. A 1.0-kg ball on the end of a string is whirled at a constant
speed of 2.0 m/s in a horizontal circle of radius 1.5 m. What is
the work done by the centripetal force during one revolution?
7. A 2.5-kg ball and a 5.0-kg ball have an elastic collision.
Before the collision, the 2.5-kg ball was at rest and the other
ball had a speed of 3.5 m/s. What is the kinetic energy of the
2.5-kg ball after the collision?
8. A bicycle wheel of radius 0.70 m is rotating at an angular speed
of 6.3 rad/s as it rolls on a horizontal surface without slipping.
What is thelinear speed of the wheel?
9. A meter stick is pivoted at the 0.50-m line. A 3.0-kg object is
hung from the 0.15-m line. Where should a 5.0-kg object be hung to
achieve equilibrium (the meter stick oriented horizontal and
motionless)?
10.
A 1.0-kg wheel in the form of a solid disk rolls along a horizontal
surface with a speed of 6.0 m/s. What is the total kinetic energy
of the wheel?
11.
Assume that an MX missile goes from rest to a suborbital velocity
of 3.50 km/s in 40.0 s. What is its average acceleration in
m/s/s?
12.
A powerful motorcycle can produce an acceleration of 3.50 m/s/s
while traveling at 90.0 km/h. At that speed the forces resisting
motion, including friction and air resistance, total 350.0 N. What
force does the motorcycle exert backward on the ground to produce
its acceleration if its mass with rider is 245 kg?
13.
Boxing gloves are padded to lessen the force of a blow. Calculate
the force exerted by a boxing glove on an opponent's face, if the
glove and face compress 6.50 cm during a blow in which the 8.00 kg
arm and glove are brought to rest from an initial speed of 10.0
m/s.
14.
Train cars are coupled together by being bumped into one another.
Suppose two loaded train cars are moving toward one another, the
first having a mass of 140,000 kg and a velocity of 0.300 m/s, and
the second having a mass of 125,000 kg and a velocity of -0.120
m/s. What is their final velocity?
15.
Engines are often rated by their torque output. A certain engine
produces a maximum torque of 225 ft*lb on its 2.00 cm diameter
crank shaft. What is this torque in N*m?
16.
Disregarding air resistance, objects fall at constant
Select one:
a. velocity
b. speed
c. distances each successive second.
d. acceleration
17.
A rock is thrown vertically into the air. At the top of its path,
its acceleration in meters per second per second is
Select one:
a. none of these
b. zero
c. greater than 9.8
d. between 0 and 9.8
e. 9.8
18.
A bullet is fired from a gun. The speed of the bullet will be the
same as the speed if the recoiling gun
Select one:
a. because momentum is conserved.
b. because momentum and velocity are both conserved.
c. if the mass of the bullet equals the mass of the gun.
d. because velocity is conserved.
e. none of these.
Check
19.
When a car is braked to a stop, its kinetic energy is transformed
to
Select one:
a. stopping energy.
b. energy of motion.
c. energy of rest.
d. heat.
e. potential energy.
20.
To kick a football so it won't topple end over end, kick it so the
force of impact extends
Select one:
a. above its center of gravity.
b. through its center of gravity.
c. below its center of gravity.
1.
length of pole will be
using pythagoras theoram
L^2 = H^2 + D^2
L = sqrt (13.4^2 + 9.54^2)
L = 16.45 m
2.
Again using pythagoras
D^2 = south^2 + west^2
D = sqrt (2.25^2 +3.15^2)
D = 3.871 m
3.
average velocty = displacement/total time
displacement = final position - initial position = 0 m
average velocity = 0/T = 0 m/sec
4.
v^2 = u^2 +2*a*s
a = 9.81 m/sec^2
s = 15 m
u = 0 m/sec
v = sqrt (u^2 + 2*a*s)
v = sqrt (0^2 + 2*9.81*15)
v = 17.15 m/sec
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