Unformatted text preview: the path of a moving object if its acceleration is
constant in magnitude at all times and (a) perpendicular
to the velocity; (b) parallel to the velocity.
10. Analyze the motion of a rock falling through water in
terms of its speed and acceleration as it falls. Assume that
the resistive force acting on the rock increases as the
speed increases.
11. Consider a small raindrop and a large raindrop falling
through the atmosphere. Compare their terminal speeds.
What are their accelerations when they reach terminal
speed? PROBLEMS
1, 2, 3 = straightforward, intermediate, challenging
= full solution available in the Student Solutions Manual and Study Guide
WEB = solution posted at http://www.saunderscollege.com/physics/
= Computer useful in solving problem
= Interactive Physics
= paired numerical/symbolic problems Section 6.1 Newton’s Second Law
Applied to Uniform Circular Motion
1. A toy car moving at constant speed completes one lap
around a circular track (a distance of 200 m) in 25.0 s.
(a) What is its average speed? (b) If the mass of the car
is 1.50 kg, what is the magnitude of the force that keeps
it in a circle?
2. A 55.0kg ice skater is moving at 4.00 m/s when she
grabs the loose end of a rope, the opposite end of
which is tied to a pole. She then moves in a circle of radius 0.800 m around the pole. (a) Determine the force
exerted by the rope on her arms. (b) Compare this
force with her weight.
3. A light string can support a stationary hanging load of
25.0 kg before breaking. A 3.00kg mass attached to the
string rotates on a horizontal, frictionless table in a circle of radius 0.800 m. What range of speeds can the
mass have before the string breaks?
4. In the Bohr model of the hydrogen atom, the speed of
the electron is approximately 2.20 106 m/s. Find
(a) the force acting on the electron as it revolves in a
circular orbit of radius 0.530 10 10 m and (b) the
centripetal acceleration of the electron.
5. In a cyclotron (one type of particle accelerator), a
deuteron (of atomic mass 2.00 u) reaches a ﬁnal speed
of 10.0% of the speed of light while moving in a circular
path of radius 0.480 m. The deuteron is maintained in
the circular path by a magnetic force. What magnitude
of force is required?
6. A satellite of mass 300 kg is in a circular orbit around
the Earth at an altitude equal to the Earth’s mean radius (see Example 6.6). Find (a) the satellite’s orbital 7. 8. 9. 10. 11. speed, (b) the period of its revolution, and (c) the gravitational force acting on it.
Whenever two Apollo astronauts were on the surface of
the Moon, a third astronaut orbited the Moon. Assume
the orbit to be circular and 100 km above the surface of
the Moon. If the mass of the Moon is 7.40 1022 kg and
its radius is 1.70 106 m, determine (a) the orbiting astronaut’s acceleration, (b) his orbital speed, and (c) the
period of the orbit.
The speed of the tip of the minute hand on a town
clock is 1.75 10 3 m/s. (a) What is the speed of the
tip of the second hand of...
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 Fall '13
 Circular Motion, Force, other applications

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