Download File - BAZINGA BROWN

Name____________________________
AP Physics 1
Newton’s Laws Stage 1
1.
A hummingbird is hovering motionless beside a flower. The blue of its wings shows
that they are rapidly beating up and down. If the air pushes upward on the bird
with a force of 0.30 N, what is the weight of the hummingbird? [0.30N]
2. A bag of potatoes with weight 39.2 N is suspended from a string that exerts a
force of 46.8 N. If the bag’s acceleration is upward at 1.90 m/s2 what is the mass
of the potatoes? [4.0kg]
3. While an elevator of mass 2530 kg moves upward, the force exerted by the cable is
33.6 kN.
a. What is the acceleration of the elevator?
b. If at some point in the motion the velocity of the elevator is 1.20 m/s
upward, what is the elevator’s velocity 4.00 s later? [3.5 m/s2 up, 15 m/s up]
Mrs. Brown Newton’s Laws
4. Peta lifts a 2.0 kg stone vertically with his hand at a constant upward velocity of 1.5
m/s. What is the magnitude of the total force of the man’s hand on the stone?
[20N]
5. The forces on a small airplane (mass 1160 kg) in horizontal flight heading eastward
are as follows: gravity = 16.000 kN downward, lift = 16.000 kN upward, thurst =
1.800 kN eastward, and drag = 1.400 kN westward. At t=0, the plane’s speed is
60.0 m/s. If the forces remain constant, how far does the plane travel in the next
60.0s? [4.22 km]
Mrs. Brown Newton’s Laws
Name ____________________________
AP Physics 1
Newton’s Laws Stage 2
1.
A pulley is hung from the ceiling by a rope. A block of mass M is suspended by
another rope that passes over the pulley and is attached to the wall. The rope
fastened to the wall makes a right angle with the wall. Ignore the masses of the
rope and the pulley. Find
a. The tension in the rope from which the pulley hangs
b. The angle that the rope makes with the ceiling
[sqrt2 Mg, 45o]
Mrs. Brown Newton’s Laws
2.
Spring scale A is attached to the floor and a rope runs vertically upward, loops
over the pulley, and runs down on the other side to a 120 N weight. Scale B is
attached to the ceiling and the pulley is hung below it. What are the readings of
the two spring scales A and B? Neglect the weights of the pulley and scales? [120,
240]
Mrs. Brown Newton’s Laws
Name ____________________________
AP Physics 1
Newton’s Laws Stage 3
1. A block of mass m1 kg rests on a frictionless horizontal surface. A second block of
mass m2 = 2.0 kg hangs from an ideal cord of negligible mass that runs over an ideal
pulley and then is connected to the first block. The blocks are released from rest. [3.9
m/s2 right, 3.9 m/s2 down, 2.7 m/s right, 2.8 m right, 1:0.31m rt, 2:0.31m down]
a. Find the acceleration of the two blocks after they are released.
b. What is the velocity of the first block 1.2 s after the release of the blocks,
assuming the first block does not run out of room on the table and the second
block does not land on the floor?
c. How far has block 1 moved during the 1.2 s interval?
d. What is the displacement of the blocks from their initial positions 0.40 s after
they are released?
Mrs. Brown Newton’s Laws
2.
Two blocks are connected by a lightweight, flexible cord that passes over a
frictionless pulley. If m1 = 3.6 kg and m2 = 9.2 kg, and block 2 is initially at rest 140 cm
above the floor, how long does it take block 2 to reach the floor? [0.81s]
Mrs. Brown Newton’s Laws
Name _____________________________
AP Physics 1
Newton’s Laws Stage 4
The coefficient of static friction between a block and a horizontal floor is 0.40, while the
coefficient of kinetic friction is 0.15. The mass of the block is 5.0 kg. A horizontal force
is applied to the block and slowly increased. [20N, 12N]
a. What is the value of the applied horizontal force at the instant that the block
starts to slide?
b. What is the net force on the block after it starts to slide?
Mrs. Brown Newton’s Laws
Name _____________________________
AP Physics 1
Newton’s Laws Stage 5
1.
Lady Gaga has a mass of 76.2 kg. She is riding in an elevator that has a downward
acceleration of 1.37 m/s2. With what magnitude forces does the elevator floor
push upward on Gaga? [642N]
2. Justin Bieber standing on a bathroom scale inside an elevator. His weight is 140 lb,
(yeah right) but the reading of the scale is 120 lb. [1.4 m/s2 down, no]
a. Assuming Mrs. Brown does not cut the cord so that the elevator plummets to
the earth, what is the magnitude and direction of the acceleration of the
elevator?
b. Can you tell whether the elevator is speeding up or slowing down?
Mrs. Brown Newton’s Laws