Download Vectors Review for Test 2014 Answers 1

Physics 12
Warren—NKEC
Name: __________________________
Velocity Vectors
1. A car traveling at a constant speed of 30m/s passes a highway patrol car, which is at rest.
The police officer accelerates at a constant rate of 3.0 m/s2 and maintains this rate of
acceleration until he pulls next to the speeding car. Assume that the police car starts to
move at the moment the speeder passes his car. Determine:
a) the time required for the police officer to catch the speeder
b) the distance traveled during the chase
2. A boat whose speed in still water is 4.1m/s must aim upstream at an angle of 41° with
respect to the shore in order to travel directly across the stream.
a) What is the speed of the current?
b) What is the resultant velocity of the boat with respect to the shore?
3. An airplane, whose speed in still air is 200km/h, is flying with its nose pointed 34° [N of
E]. If there is a wind blowing 50km/h towards the west, what is the ground speed of the
airplane?
4. Bob is a soccer player who has just scored the winning goal in the game. Bob, who is also
an observant physics student, noticed that when he received the pass, the soccer ball was
moving 4.8 m/s 8° N of E and that after he kicked the ball it was moving at 25 m/s 41° E of
S. What is the ball's change in velocity?
Torque and Translational Rotation
5. A 0.75 kg board of length 2.60 m initially rests on two supports as shown.
a) What maximum distance, x, from the right-hand support can a 1.20 kg bird walk before
the board begins to leave the left-hand support?
b) What force does the right-hand support exert on the board at that instant?
6. A 6.0 m uniform beam of mass 32 kg is suspended horizontally by a hinged end and a
cable. A 93 kg object is connected to one end of the beam.
What is the magnitude and direction of the reaction force R that the hinge exerts on the
beam?
7. An object of mass, m, is suspended by two cords connected to a wall and to a 5.0 kg
block resting on a table as shown.
A coefficient of friction of 0.47 exists between the 5.0 kg block and the table. What is the
maximum mass, m, that can be hung from the cords before the 5.0 kg block begins to
move?
8. A 110 kg object is supported by two ropes attached to the ceiling. What is the tension T
in the right-hand rope?
9. A 220 N bag of potatoes is suspended from a rope as shown in the diagram. A person
pulls horizontally on the bag with a force of 80 N.
Dynamics
10.Three blocks have masses 1.0 kg, 7.0 kg and 5.0 kg as shown. The horizontal surface is
frictionless. What is the magnitude of the acceleration of the system?
11.A 2.0 kg block is sliding down a 15° incline. The coefficient of friction is 0.62. At some
position the block has a speed of 7.0 m s. What distance d will this block move before
coming to rest?
12.A girl applies a 140 N force to a 35 kg bale of hay at an angle of 28° above horizontal.
The friction force acting on the bale is 55 N. What will be the horizontal acceleration of the
bale?
13.A cart on a frictionless surface is attached to a hanging mass of 8.2 kg. If this system
accelerates at 3.5 m/s2, what is the mass m of the cart?
14.A 6.0 kg block is held at rest on a horizontal, frictionless air table. Two forces are pulling
on this block in the directions shown in the diagram below.
What will be the magnitude of the acceleration on the 6.0 kg block at the moment it is
released?
15.In the diagram, the tension in the cord connecting the hanging mass and cart is 43 N.
Determine the mass of the cart.