**General Physics I**

**Final Exam Primer**

**Name_________________________**

**1. **The standard kilogram is a
platinum-iridium cylinder 39-mm in height and 39mm in diameter. What is the density of the material?

___1.
21.0 N

___2.
20 g/ cm ^{3}

___3. 21464 kg / m^{3}

___4. 5366 kg / m^{3}

**2. **A temperature of 88 degrees
Fahrenheit is equivalent to how many Celsius degrees?

___1. 31

___2. 49

___3. 56

___4. 158

**3. ** A weight
lifter can lift a 400-lb. barbell over his head and hold it there for 3 seconds
before setting it down. The net work that he has done

___1.
depends on the weight of the barbell.

___2.
depends on the time that the weight was held.

___3.is
positive

___4.is
equal to zero.

**4. **A man
pushes a 100-kg crate across a horizontal floor. The work done

by gravity on the load

___ 1. depends on the weight of the load.

___ 2. cannot be calculated without more information.

___ 3. is equal to zero.

___4. 1960 joules

**5. **A man
pushes a 200-kg crate 50 meters across a horizontal floor in 25 seconds. The work done by the man on the load is

___ 1800 joules.

___ 2. Is equal to zero

___ 3. 1600 joules.

___ 4. 98000 joules

___ 5. Cannot be calculated.

**Name_____________**

**6**. Is
it possible for an object’s instantaneous velocity and instantaneous
acceleration to be of opposite sign at the same moment in time?

___ 1. yes

___ 2. no

___ 3. need more information

**7. **A disk is rotating at a
constant rate about a vertical axis through its center.

Point
*Q *is twice as far from the center of
the disk as point *P *is. The angular

velocity
of *Q *at a given time is

___
1. twice as big as *P*’s.

___
2. the same as *P*’s.

___
3. half as big as *P*’s.

___
4. none of the above.

**8**. Sum the following vectors
and express the sum in polar (R,q) form.

A
= 12
x + 15 y

C
= 5
x + -5 y

D = - 30 x
+ 17 y

E = (15 , 30^{o})

**9. **A
tower has dimensions of length = 3.28
ft, width =1574.80 in, depth = 9.8425 yards. What is its total volume? Express your answer in SI units.

**10. ** The distance
of one lap around a circular dirt bike track is 1.25 km. A rider moving
counterclockwise at constant speed completes a lap in 1.8 minutes. What is his angular velocity? What is the magnitude of his tangential
velocity?

**11.** A 3-kg mass
rests on a plane inclined at an angle of 30° as shown and has a coefficient of
static friction *µ*_{S} = 0.4.

**a.
**What is the largest mass_{ }*m*_{2}
that can be attached to the string passing over the pulley without causing the
mass *m*_{1} to move_{ }?
**b.** If the mass *m*_{2} is changed to 5 kg and the 3kg block accelerates up
the plane with *a* = 3.3 m/s^{2},
what is the coefficient of kinetic friction *m*** _{k}**?

**12**. A
2500-kg car moving east at 24 m/s collides with a 3200-kg car moving north at
14 m/s. The cars stick together after
the collision.

a. Find
the velocity (magnitude and direction) of the cars at the moment of impact.

b. The
cars slide to a halt over a distance of 15 meters. What is the coefficient of kinetic friction
of the road? What is the work done by
friction?

** 13. **A hot air balloon floats
motionless at 0.33 km above the ground. A sandbag is released, and the balloon
rises with constant acceleration of 0.330 m/s^{2}. How long does it
take for the sandbag to fall to earth?
What is its velocity just as it strikes the ground? How high is the
balloon at the moment the sandbag strikes the ground? (show your work)

**14**. A 25 gram projectile is shot from a spring
loaded gun .The spring is compressed 6 cm.
The projectile strikes and embeds itself in a pendulum bob that is 200
grams . After the collision the bob and bullet
reach a maximum height of 16 centimeters.
Determine the spring constant , **K**,
of the spring gun (cite appropriate units).

**15.** The pendulum described in question 14 has a
length of 16 cm from pivot to the bob.
What is the angular velocity of the bob at the instant the bullet
strikes? What is the maximum angle from
vertical that the pendulum attains?