Download Physics 37

Caution: These are not the only kinds of problems that may occur on the final exam.
See the weekly quizzes and homework for a greater variety of possibilities.
Physics 37
Practice Exam
1. A 10-kg block on an inclined plane is connected to a 2.00-kg sphere by a cable running over a
pulley. The Block starts from rest and then slides 2.80 meters down the plane. Friction from all
sources absorbs a total of 3.00 Joules of energy during the process. How fast will the block be
moving when it reaches the bottom of the plane?
NAME _____________________________
2. A 5.80-kg blob of bubble gum moves to the right with an initial velocity vi = 12.3 m/s. It
collides with a 3.2-kg blob of bubble gum initially at rest. After the collision they stick
together and move to the right with some final velocity. What percent of the initial kinetic
energy of the system is lost in the collision?
3. (4 pts) When a truncated cone is submerged horizontally in water, the larger surface (A2)
experiences a larger total force than the smaller surface (A1). Does this mean the cone
will accelerate to the left? Why/why not?
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NAME _____________________________
4. A rod of length 30.0 cm has a linear density (mass per unit length) given by
 = 50.0 + 20.0x
where x is the distance from one end, measured in meters, and  is in grams per meter. What
is the mass of the rod?
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NAME _____________________________
5. A machine part rotates at an angular speed of 0.060 rad/sec; its speed is then increased to
2.20 rad/sec at an angular acceleration of 0.70 rad/s2. Find the angle through which the
part rotates before reaching its final speed.
6. Three vectors are given by A = 5i + 2j +3k, B = 6i +4j  2k and B = 6i +4j  2k.
Evaluate the quantity (A x B)C.
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NAME _____________________________
7. A solid disk rolls without slipping down a curved ramp as shown below. It starts from rest
at a height of 4.20 meters above the lowest point. Find the linear velocity of the disk at
the bottom of the ramp. (Idisk = ½ MR2)
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NAME _____________________________
8. A horizontal platform in the shape of a circular disk rotates freely in a horizontal plane
about a frictionless, vertical axle. The platform has a mass M = 100 kg and a radius R =
2.00 m. A student whose mass is m = 60 kg walks slowly from the rim of the disk toward
its center. If the angular speed of the system is 2.00 rad/sec when the student is at the rim,
what is the angular speed when she reaches a point r = 0.50 m from the center? (Idisk = ½
MR2, Ipoint mass = m r2 )
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NAME _____________________________
9 . A uniform sign of weight 50.0 Newtons, with dimensions shown below, hangs from a
light, horizontal beam hinged at the wall and supported by a cable. Determine (a) the
tension in the cable and (b) the components of the reaction force exerted by the wall on
the beam.
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NAME _____________________________
10. Four asteroids of equal mass M = 3.00 X 1015 kg are located at the corners of a square,
100 km on a side. (a) Calculate the total gravitational potential energy of the system. (b)
If the asteroids are released from rest while on the corners of the square, they will fall
inward towards each other. How fast will they be moving when the square has shrunk to
a dimension having 10 km on a side?
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NAME _____________________________
11. At what distance from the sun will a planet have a period of three Earth years?
Mass of Sun M = 2.00 X 1030 kg, G = 6.67 X 10-11 N-m2/kg2
12 Water is forced out of a fire extinguisher by air pressure as shown below. How much
gauge air pressure in the tank is required for the water jet to have a speed of 30.0 m/s
when the water level is 0.500 meter below the nozzle?
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NAME _____________________________
Spring potential energy:
Us = ½kx2
W  F x
Work done by a conservative force:
Wg = - U = -(Uf – Ui)
W  ( F cos  )x
Linear Momentum:
p = mv (kg-m/s)
Work-Energy Theorem:
Impulse:
I = Ft = p = mvf - mvi
Wnet  KE
Wnet = ½mvf 2 - ½mvi 2
For every collision momentum is
conserved
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KE  mv 2
2
Perfectly inelastic collisions:
Gravitational potential energy:
m1v1i + m2v2i
=
(m1 + m2)vf
Ug = mgy
Rotational motion:
  i   t
Kinetic Energy:
1
2
1
  i t   t 2
2
2
2
  i  2
Rotational : KEr  I  2 ,
Translational: KEt = ½ mv2
Total Kinetic Energy:
KEtotal
Tangential speed:
vt  r
= KEtranslational + KErotational
Tangential acceleration:
at  r
Tangential speed:
vt  r
s = r,
v = r,
s = r,
v = r,
a = r
 = F(sin)r
l = lever arm
 = Fl, where
Equilibrium:
=0
Non-equilibrium:
  = I
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a = r
 = F(sin)r
l = lever arm
 = Fl, where
Equilibrium:
=0
Non-equilibrium:
  = I
NAME _____________________________
L=rxp
 = dL/dt
L = I
P
F
A
( Pa )
P  P0   gh
When external torque = zero: Linitial =
Lfinal
A X B = (AyBz – AzBy)i + (AzBx – AxBz)j +
(AxBy – AyBx)k
Buoyancy Force, B = weight in air –
weight in fluid
Area of a circle = A = r2
| A X B | = ABsin
Buoyancy force on a submerged object:
A  B = AxBx +AyBy + AzBz
Fg  G
m1m2
r2
B =
fluid Vobject g
where G = 6.67 X
Fluid flow:
10-11 N-m2/kg2
Flow rate Q(m3/s) = vA
acceleration due to gravity, g = GME/(RE
+ h)2
v1A1 = v2A2
Bernoulli’s Principle: P1 + gy1 + ½ v12 = P2
+ gy2 + ½  v22
Gravitational potential energy between
two masses, U = Gm1m2/r
For objects near earth, gravitational
potential energy U = GMEm/(RE + h)
Kepler’s 3rd law of planetary motion:
T2 = (42/GMsun)/a3 where Msun is the
mass of the Sun: 2.0 X 1030 kg, and
a = semimajor axis
of the ellipse
Wnet = K, U = K,
Density:
Pressure:
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