Chapter 4 Solutions
Poe
13 11. The position r of a particle moving in an xy plane is given by r = (2.00t3 5.00t) + (6.00 -7.00t4), with r in meters and t in seconds. In unit-vector
notation, calculate (a) r, (b) v, find (c) a for t = 2.00 s. (d) What is t

Chapter 9 Solutions
Poe
2 2. A three-particle system, with masses ml = 3.0 kg, m2 = 4.0 kg, and m3= 8.0 kg. The
scales on the axes are set by xs = 2.0 m and ys, = 2.0 m. What are (a) the x coordinate and
(b) the y coordinate of the system's center of mass

7ImpulseandMomentum
Isaac Newton wrote out his theory differently than we write them today. He used the concept of
impulse and momentum to solve practical problems in physics.
7.1 Center of Mass
We start with a very useful concept of the center of mass. U

8 Rotation
Rotating objects are very common in nature and we need to extend our formulation to include
rotating objects. Many of the equations, and thus the mathematics, are the same as before, just
the notation is different.
8.1 Rotation relation with li

6Energy
Of all the great things Isaac Newton did, he didnt understand the importance of energy. The
importance of conservation of energy was difficult to see because of the presents of friction. Our
Universe seems to be passionate about energy: you can ne

1Introduction
The Universe began about 13 billion years ago. At that moment, all the space and matter that we
know today was created. But, more importantly, the rules that govern our reality were set forth.
Rules such as conservation laws, inertia, forces

5NewtonsLaws
Isaac Newton lived in England and went to Trinity College in Cambridge in 1661. The great
plague closed the college in 1665 and Newton went home to his parents apple orchid. There he
spent the most productive years of any scientist. He had br

Phys 50
Mid-Term 1
Name: (Last)_
Dr. Ray Kwok
(First)_
o
1. A snowball rolls off a barn roof that slopes downward at an angle of 40 . The edge of the roof
is 14 m above the ground, and the snowball has a speed of 7 m/s as it rolls off the roof. Ignore
air

Chapter 10 Solutions
Poe
2
3
6 4. The angular position of a point on a rotating wheel is given by = 2.0 + 4.0t + 2.0t ,
where is in radians and t is in seconds. At t = 0, what are (a) the point's angular position
and (b) its angular velocity? (c) What is

Chapter 13 Solutions
Poe
6 8.
Using F = GmM/r2, we find that the top most mass pulls upward on the one at the origin with 1.9
108 N, and the rightmost mass pulls rightward on the one at the origin with 1.0 108 N.
Thus, the (x, y) components of the net fo

Chapter 8 Solutions
Poe
4 2. A frictionless roller-coaster car of mass m = 825 kg tops the first hill with speed Vo =
17.0 m/s at height h = 42.0 m. How much work does the gravitational force do on the car
from that point to (a) point A, (b) point B, and

Chapter 3 Solutions
Poe
9 11. (a) In unit-vector notation, what is the sum r = a +b if a = (4.0 m) +-(3.0
m) and b = (-13.0 m) + (7.0 m)? What are the (b) magnitude and (c) direction
of r = a +b ?
Write r = a + b . When not explicitly displayed, the units

Chapter 2 Solutions
Poe
8th 9th editions
9 11. You are to drive to an interview in another town, at a distance of 300 km on
an expressway. The interview is at 11:15 A.M. You plan to drive at 100 km/h, so
you leave at 8:00 A.M. to allow some extra time. Yo

Chapter 7 Solutions
Poe
5 5. A father racing his son has half the kinetic energy of the son, who has half the mass
of the father. The father speeds up by 1.0 m/s and then has the same kinetic energy as the
son. What are the original speeds of (a) the fath

Chapter 6 Solutions
Poe
8 2. In a pickup game of dorm shuffleboard, students crazed by final exams use a
broom to propel a calculus book along the dorm hallways. If the 3.5 kg book is
pushed from rest through a distance of 0.90 m by the horizontal 25 N fo

Chapter 5 Solutions
Poe
2 2. Two horizontal forces act on a 2.0 kg chopping block that can slide over a
frictionless kitchen counter, which lies in an xy plane. One force is F1= (30 N)i +
(4.0 N)j. Find the acceleration of the chopping block in unit-vecto

Chapter 12 Solutions
Poe
7 11.
We take the force of the left pedestal to be F1 at x = 0, where the x axis is along the diving board.
We take the force of the right pedestal to be F2 and denote its position as x = d. W is the weight
of the diver, located a

Chapter 11 Solutions
Poe
11 9. A solid ball rolls smoothly from rest (starting at height H = 6.0 m) until it leaves the
horizontal section at the end of the track, at height h = 2.0 m. How far horizontally from
point A does the ball hit the floor?
To find

Chapter 15 Solutions
Poe
11 9. (a) Making sure our calculator is in radians mode, we find
FG b g IJ = 3.0 m.
H
3K
x = 6.0 cos 3 2.0 +
(b) Differentiating with respect to time and evaluating at t = 2.0 s, we find
v=
b g FGH b g IJK
dx
= 3 6.0 sin 3 2.0 +
=

Phys 50
1.
Sample Mid-Term 1
Dr. Ray Kwok
You are on the roof of the physics building, 46.0 m above the ground. Your professor, who is
1.80 m tall, is walking alongside the building at a constant speed of 1.20 m/s. If you wish to drop
an egg on your profe