Single
Objective:
Date: ________
Statics and Dynamics Review
Homework: Study for Test #3: Statics and Dynamics
AP Physics
Date ___________
Mr. Mirro
Statics and Dynamics Review
1) As shown, a 1.0 kg ball is hung from 2 strings of
unequal length. The tensions in the strings must
satisfy which of the following relations?
a)
T =
1
c) T
1
e) T 1 -
T
<
b) T
2
T
2
T2 =
d) T
(c)
>
1
+
1
T
T2
T
1
T
2
2
= mg
mg
2) A ball falls straight down through the air under the influence of gravity. There is a retarding force F
on the ball with magnitude given by F = bv, where v is the speed of the ball and b is a positive
constant. The magnitude of the acceleration a of the ball at any time is equal to which of the
following?
a) g - b
b) g - (bv ÷ m)
c) g + (bv ÷ m)
d) g ÷ b
e) bv ÷ m
2
3) A 5.0 kg concrete block is lowered with a downward acceleration of 2.8 m/s by means of a rope.
The force which the block exerts on the rope is
a) 14.0 N, up
b) 14.0 N, down
c) 35.0 N, up
d) 35.0 N, down
e) 49.0 N, up.
4) The coefficient of kinetic friction
a) is in the direction of the frictional force
c) is the ratio of normal force to area
e) is the ratio of frictional force to the normal force.
b) is in the direction of the normal force
d) can have units of Newtons
5) As shown, a block of mass m is pulled along a rough horizontal floor
to the right by an applied force F. The normal force exerted on the
block by the floor is (d)
a) mg
b) mg - F cos h
c) mg + F cos h
F
O
d) mg - F sin h
e) F sin h
For Questions 6) and 7), refer to the diagram shown, in which a plane
5 meters in length is inclined at an angle of 37 degrees. A block of
weight 20 Newtons is placed on the plane and is permitted to slide down.
5m
6) The mass of the block is most nearly (d)
a) 1.0 kg
b) 1.2 kg
c) 1.6 kg
d) 2.0 kg
3m
o
37
e) 2.5 kg.
4m
7) The magnitude of the normal force exerted on the block by the plane is most nearly
a) 10 N
b) 12 N
c) 16 N
d) 20 N
e) 33 N.
F
8) As shown, a heavy wooden block is dragged along a rough steel
plate by the applied force F.
compared to that in (i) is
a) the same
F
The force of friction in (ii) as
(c)
b) greater
c) less
(i)
( ii )
d) less for some angles and more for others
e) can be less or greater, depending on the magnitude of the applied force.
9) A box rests on a rough board 10.0 m long. When one end of the board is slowly raised to a height
of 6.0 m above the other end, the box begins to slide. The coefficient of static friction is
a) 0.90
b) 0.25
c) 0.40
d) 0.58
e) 0.75.
10) A heavy ball is suspended as shown. A quick jerk on the lower string will
upper string
break that string but a slow pull on the lower string will break the upper
string. The first result occurs because
a) the force is too small to move the ball
d) air friction holds the ball back
(c)
b) action and reaction
e) the ball is too dark.
c) the ball has inertia
lower string
11) Finding her car stuck in the mud, a bright graduate of a good physics course ties a strong rope to the back bumper
of the car, and the other end to a tree as shown. She pushes at the midpoint of the rope with her maximum effort,
which she estimates to be a force Fp ≈ 275 N. The car just begins to budge with the rope at an angle which she
estimates to be about θ = 10°. Neglecting the mass of the rope, with what force (T2) is the rope pulling on the car ?
Fp
Tree
T1
T2
θ
θ
12) A block having mass m1 is at rest on a rough inclined plane having a coefficient of static friction μs. A hanging mass
m2 is connected over a massless frictionless pulley as shown. The rope does not stretch and may be considered
massless as well.
a. Develop an equation for the magnitude of the frictional force in terms of m1, m2, g and
θ ONLY!
m1
m2
b. If the cord is cut, mass m2 will be accelerated at a rate equal to the acceleration due to gravity (g). However, m1
will have a different acceleration as it slides down the plane. Derive an equation for the acceleration of m1 in
terms of:
μk, g and θ ONLY !
c. If the coefficient of static friction is μs = 0.40 and the coefficient of kinetic friction μk = 0.20, determine the
acceleration of mass m1 as it slides down the incline.