PH1031C_1_Test_3

If an object moves with constant velocity in a straight line, which of the following statements is true?

• There are no forces acting on the object.

• The net force on the object is zero.

• There is a constant force in the direction of motion.

• There is a constant force in the direction opposite of motion.

A ball of mass m is suspended by a string from the ceiling inside an elevator. If the elevator is moving upward with a constant speed, the tension in the string

• is greater than mg.

• is equal to mg.

• is less than mg.

• depends on the speed of the elevator.

Two blocks, with masses 1 kg and 2 kg, are released simultaneously on an inclined plane that makes an angle of θ with the horizontal. Select true statements about their acceleration after being released.

• Both blocks accelerate at a rate of g.

• Both blocks accelerate at a rate of g*cosθ

• Both blocks accelerate at a rate of g*sinθ

• The 1-kg block accelerates two times faster than the 2-kg block.

• The 2-kg block accelerates two times faster than the 1-kg block.

The graph to the right shows the velocity of an object as a function of time as it moves along the x-axis. Which of the graphs below best shows the net force versus time for this object?

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• 
• 
• 
• 

When you apply an upward force of magnitude F to a block of mass 2.00 kg, the block accelerates upward at 3.00 m/s^2. You can ignore any forces exerted on the block by the air. Which force is the largest in magnitude?

• F

• the net force on the block

• the gravitational force on the block

If you see a stationary pendulum hanging vertically inside a closed compartment, what could be the possible states of motion of the compartment?

• At rest

• Acceleration

• Deceleration

• Uniform linear motion

If you observe a stationary pendulum inside a closed compartment, with its string making an angle θ with the vertical direction, what could be the possible states of motion of the compartment?

• At rest

• Acceleration

• Deceleration

• Uniform linear motion

A cart (weight w1) is attached by a lightweight cable to a bucket (weight w2) as shown. The ramp is frictionless. When released, the cart accelerates up the ramp. Which of the following is a correct free-body diagram for the cart?

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• 
• 
• 
• Not enough information is given to decide.

A cart (weight w1) is attached by a lightweight cable to a bucket (weight w2) as shown. The ramp is frictionless. The pulley is frictionless and does not rotate. When released, the cart accelerates up the ramp and the bucket accelerates downward. How does the cable tension T compare to w2?

• T=w2

• T>w2

• T<w2

• Two of the above are possible, depending on the acceleration.

• All three of the above are possible, depending on the acceleration.

When a bubble level is placed flat on a horizontal table, its bubble rests at the center. If the level is then pushed forward along the table, the bubble will be located in [ ] of the accelerating level.

• the center

• the front

• the back