Download 1) You push your lawnmower (mass = 15 kg) across

AP Physics: Newtons Laws and Force Diagrams
1) Object slides without friction. Solve for Weight and acceleration in terms of m, g, θ.
a. Calculate the acceleration on the weight for m = 20 kg g = 9.8 m/s² and θ = 60 º
2) Static friction prevents sliding. Solve for Weight and acceleration in terms of m, g, θ.
3) You push your lawnmower (mass = 15 kg)
across the lawn at constant speed. To do so,
you must exert 120 N of force. The handle
makes a 35° angle with the horizontal.
a. In the space under the figure, sketch a force
diagram to represent this situation.
b. What is the x-component of the force you
apply?
c. How does this compare to the frictional force which opposes your effort? Explain.
d. What is the value of the normal force?
4) A man pulls a 50 kg box at constant speed across the floor. He applies a 200 N
force at an angle of 30°.
a. Sum the forces in the x-direction. What is the value of the frictional force
opposing the motion?
b. Sum the forces in the y-direction. What is the value of the normal force?
5) A man pushes a 2.0 kg broom at constant speed across the floor. The broom
handle makes a 50° angle with the floor. He pushes the broom with a 5.0 N
force.
a.
Sum the forces in the y-direction. What is the value of the
normal force?
b.
Sum of the forces in the x-direction. What is the value of
the frictional force opposing the motion?
c.
If the frictional force were suddenly reduced to zero, what would happen to the
broom?
6) Derive the “a” acceleration system and the Tension (T) in terms of m, g, θ.
7) A passenger of mass m= 72.2 kg stands on a bathroom scale in an elevator. We are
concerned with the scale readings when the cab is stationary, and when it is moving up or
down.
(a) Find the general solution for the scale reading, whatever the vertical motion of the cab.
(b) What does the scale read if the cab is stationary or moving upward at a constant 0.50
m/s?
(c) What does the scale read if the cab accelerates upward at
?
and downward at
8) A 5.0 kg salmon is weighed by hanging it from a fish scale attached to the ceiling of an
elevator. What is the apparent weight of the salmon,
moves with an upward acceleration of
of
, if the elevator (a) is at rest, (b)
, or (c) moves with a downward acceleration
?
9) A trained sea lion slides from rest with constant acceleration down a 3.0 m long ramp
into a pool of water. If the ramp is inclined at an angle of
above the horizontal. (a) Find
the acceleration the sea lion has down the plane. (b) Find how long the sea lion takes to
make a splash in the pond.
10) 1) A block of mass
slides on a frictionless tabletop. It is connected to a string
that passes over a pulley and suspends a mass
. Find the acceleration of the
masses and the tension in the string.
Atwood's Machine
11) The figure shows two blocks connected by a cord that passes over a massless, frictionless
pulley. The lighter block
has a mass m = 1.3 kg and the heavier block
has a m = 2.8
kg. Find the magnitudes of the accelerations of the two blocks and the magnitude T of the
force on each block from the cord.
12) In the figure a crate of dilled pickles with mass
makes an angle of
moves along a plane that
with the horizontal. The crate is connected to a crate of
pickled dills with mass
by a taut, massless cord that runs over a frictionless,
massless pulley. The dills descend with constant velocity. (a) What are the magnitude and
direction of the frictional force on the pickles from the plane? (b) What is
?
13) To hang a 6.20 kg pot of flowers, a gardener uses two wires–one attached horizontally to
a wall, the other sloping upward at an angle of
the tension in each wire.
and attached to the ceiling. Find
AP Physics Application of Newton’s Laws Circular Motion
14) A 1200 kg car rounds a corner of radius r = 45 m. If the coefficient of static
friction between the tires and the road is
car can have in the corner without skidding?
, what is the greatest speed the
15) The figure represents a stock car of mass m = 1600 kg traveling at a constant
speed v = 20 m/s around a flat, circular track of radius R = 190 m. For what value
of
between the track and the tires of the car will the car be on the verge of
sliding off the track?
16) If a roadway is banked at the proper angle, a car can round a corner without any
assistance from friction between the tires and the road. Find the appropriate angle
for a 900 kg car traveling at 20.5 m/s in a turn of radius 85.0 m.
17) While driving along a country lane with a constant speed of 17.0 m/s, you
encounter a dip in the road. The dip can be approximated as a circular arc, with
radius of 65.0 m. What is the normal force exerted by a car seat on a 80.0 kg
passenger when the car is at the bottom of the dip?
18) In a 1901 circus performance, Allo "Dare Devil" Diavolo introduced the stunt of
riding a bicycle in a loop-the-loop. Assuming that the loop is a circle with radius R =
2.7 m, what is the least speed v Diavolo could have at the top of the loop to remain in
contact with it there?
Applications of Newton’s Laws and Circular Motion
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