Unit 2 MC Practice 1

A rock attached to a string swings in a vertical circle, as shown above, with negligible air resistance. Which of the following diagrams could correctly show all the forces on the rock when the string is in the position above? (I can't add pictures so i'll describe the graphs) A) an arrow pointed left B) an arrow pointed down C) an arrow pointed left and an arrow pointed down D) an arrow pointed left, an arrow pointed down, and an arrow pointed right E) an arrow pointed down and an arrow pointed right

C) an arrow pointed left and an arrow pointed down

A 50.0 N box is at rest on a horizontal surface. The coefficient of static friction between the box and the surface is 0.50, and the coefficient of kinetic friction is 0.30. A horizontal 20.0 N force is then exerted on the box. The magnitude of the acceleration of the box is most nearly A) 0 m/s^2 B) 0.5 m/s^2 C) 1.0 m/s^2 D) 4.0 m/s^2

A) 0 m/s^2

A 100 kg cart goes around the inside of a vertical loop of a roller coaster. The radius of the loop is 3 m and the cart moves at a speed of 6 m/s at the top. The force exerted by the track on the cart at the top of the loop is A) 200 N B) 800 N C) 1000 N D) 1200 N E) 2200 N

A) 200 N

A student wants to determine the coefficient of static friction μ between a block of wood and an adjustable inclined plane. Of the following, the minimum additional equipment the student needs to determine a value for μ is A) protractor only B) timer only C) protractor and timer D) meterstick and timer E) meterstick and string

A) protractor only

A block is projected up a frictionless plane with an initial speed vo. The plane is inclined 30° above the horizontal. What is the approximate acceleration of the block at the instant that it reaches its highest point on the inclined plane? A) Zero B) 5 m/s2 down the incline C) 10 m/s2 down the incline D) 10 m/s2 up the incline E) It cannot be calculated without knowing the value of vo

B) 5 m/s2 down the incline

A kitten sits in a lightweight basket near the edge of a table. A person accidentally knocks the basket off the table. As the kitten and basket fall, the kitten rolls, turns, kicks, and catches the basket in its claws. The basket lands on the floor with the kitten safely inside. If air resistance is negligible, what is the acceleration of the kitten-basket system while the kitten and basket are in midair? A) The acceleration is directed downward with magnitude less than g because the basket is light. B) The acceleration is directed downward with magnitude equal to g because the system is a projectile. C) The acceleration fluctuates because of the rolling, turning, and kicking motion of the kitten. D) The acceleration cannot be determined without knowing how hard the basket is pushed.

B) The acceleration is directed downward with magnitude equal to g because the system is a projectile.

A box is given a sudden push up a ramp. Friction between the box and the ramp is not negligible. Which of the following diagrams best represents the directions of the actual forces acting on the box as it moves upward after the push? (I can't add pictures so i'll describe the graphs) A) an arrow pointed up, an arrow pointed down the slope, and an arrow pointed straight toward the ground B) an arrow pointed up, an arrow pointed down the slope, an arrow pointed straight toward the ground, and an arrow pointing up the slope C) an arrow pointed up, an arrow pointed straight toward the ground, and an arrow pointing up the slope D) an arrow pointed up, an arrow pointed down the slope, an arrow pointed toward the ground at an angle, and an arrow pointing up the slope E) an arrow pointed up, an arrow pointed toward the ground at an angle, and an arrow pointing up the slope

B) an arrow pointed up, an arrow pointed down the slope, an arrow pointed straight toward the ground, and an arrow pointing up the slope

To analyze the characteristics and performance of the brakes on a 1500 kg car, researchers collected the data shown in the table above. It shows the car's speed when the brakes are first applied and the corresponding braking distance required to stop the car. The magnitude of the average braking force on the car is most nearly A) 75,000 N B) 30,000 N C) 12,000 N D) 1600 N

C) 12,000 N

An object of mass 10 kg10 kg is released from rest above the surface of a planet such that the object's speed as a function of time is shown by the graph above. The force due to gravity exerted on the object is most nearly A) 3.5 N B) 7 N C) 35 N D) 70 N

C) 35 N

A person is running on a track. Which of the following forces propels the runner forward? A) The normal force exerted by the ground on the person B) The normal force exerted by the person on the ground C) The force of friction exerted by the ground on the person D) The force of friction exerted by the person on the ground

C) The force of friction exerted by the ground on the person

A uniform spool is suspended from a vertical wall by a string attached to the spool's thin axle. The axle is horizontal, as shown above. The wall is smooth, so it exerts no frictional force on the spool. The tension in the string is 2.6 N. What is the weight of the spool? A) 0.5 N B) 1.0 N C) 1.2 N D) 2.4 N E) 2.6 N

D) 2.4 N

A small cart is rolling freely on an inclined ramp with a constant acceleration of 0.50 m/s^2 in the -x direction. At time t = 0, the cart has a velocity of 2.0 m/s in the +x-direction. If the cart never leaves the ramp, which of the following statements correctly describes the motion of the cart at a time t > 5 s? A) The cart is traveling in the +x-direction and is slowing down. B) The cart is traveling in the +x-direction and is speeding up. C) The cart is traveling in the -x-direction and is slowing down. D) The cart is traveling in the -x-direction and is speeding up.

D) The cart is traveling in the -x-direction and is speeding up.

A ladder at rest is leaning against a wall at an angle. Which of the following forces must have the same magnitude as the frictional force exerted on the ladder by the floor? A) The force of gravity on the ladder B) The normal force exerted on the ladder by the floor C) The frictional force exerted on the ladder by the wall D) The normal force exerted on the ladder by the wall

D) The normal force exerted on the ladder by the wall

A spaceship is traveling from Earth to the Moon. Which of the following is true of the gravitational force on the ship due to the two objects when the ship is equidistant from Earth and the Moon? A) There is no net force because the ship is beyond the influence of Earth and the Moon. B) There is no net force because the forces exerted by Earth and the Moon balance. C) There is a net force because the force exerted by Earth is smaller than that exerted by the Moon. D) There is a net force because the force exerted by Earth is greater than that exerted by the Moon. E) There is a net force because the ship must be accelerating toward the Moon.

D) There is a net force because the force exerted by Earth is greater than that exerted by the Moon.

A planet with half Earth's mass and half Earth's radius is discovered. What would an astronaut who weighs 800 N on Earth weigh on the planet? A) 100 N B) 200 N C) 400 N D) 800 N E) 1600 N

E) 1600 N

A block on a horizontal surface of negligible friction is placed in contact with an ideal spring, as shown above. The block is moved to the left so that the spring is compressed a distance x from equilibrium and then released from rest. The block has kinetic energy K1 when it separates from the spring. When the spring is compressed a distance 2x and the block is released from rest, the kinetic energy of the block when it separates from the spring is A) K1/2 B) K1 C)√2K1 D) 2K1 E) 4K1

E) 4K1

A block of mass 2 kg is suspended from a rope, as shown above. If the tension in the rope is 10 N, the acceleration of the block is most nearly A) zero B) 2 m/s^2 up C) 2 m/s^2 down D) 5 m/s^2 up E) 5 m/s^2 down

E) 5 m/s^2 down

A car with speed v and an identical car with speed 2v both travel the same circular section of an unbanked road. If the frictional force required to keep the faster car on the road without skidding is F, then the frictional force required to keep the slower car on the road without skidding is A) 4F B) 2F C) F D) F/2 E) F/4

E) F/4

A block moving to the right on a level surface with friction is pulled by an increasing horizontal force also directed to the right. As the applied force increases, which of the following is true of the normal force and the frictional force on the block? A) Normal Force --> Increases Frictional Force --> Increases B) Normal Force --> Increases Frictional Force --> Remains constant C) Normal Force --> Remains constant Frictional Force --> Increases D) Normal Force --> Remains constant Frictional Force --> Decreases E) Normal Force --> Remains constant Frictional Force --> Remains constant

E) Normal Force --> Remains constant Frictional Force --> Remains constant

The horizontal wire shown on the right in the figure above will break when the tension in it exceeds the value Tmax. What is the maximum mass M that the hanging object can have without the horizontal wire breaking? (Assume the wire on the left does not break prior to the horizontal wire breaking.) A) Tmax/g B) Tmax/gsinθ C) Tmax/gcosθ D) Tmax/gtanθ E) Tmaxtanθ/g

E) Tmaxtanθ/g