Physics test #3

A force of 25 newtons east and a force of 25 newtons west act concurrently on a 5-kilogram cart. What is the acceleration of the cart?

0 m/s2

When a 12-newton horizontal force is applied to a box on a horizontal tabletop, the box remains at rest. e force of static friction acting on the box is

12 N

As the angle between two concurrent forces of 5.0 Newtons and 7.0 Newtons increases from 0o to 180o, the magnitude of their resultant changes from

12 N to 2.0 N

Compared to the inertia of a 1-kilogram mass, the inertia of a 4-kilogram mass is

4 times as great

A 100.-kilogram cart accelerates at 0.50 meter per second squared west as a horse exerts a force of 60. newtons west on the cart. What is the magnitude of the force that the cart exerts on the horse?

60. N

A man weighing 800 Newtons is standing on a chair. In order to support the man, the chair is exerting a force of

800 N

A baseball bat exerts a force of magnitude F on a ball. If the mass of the bat is three times the mass of the ball, the magnitude of the force of the ball on the bat is

F

Earth's mass is approximately 81 times the mass of the Moon. If Earth exerts a gravitational force of magnitude F on the Moon, the magnitude of the gravitational force of the Moon on Earth is

F

Two metal spheres, A and B, possess charges of 1.0 microcoulomb and 2.0 microcoulombs, respectively. In the diagram below, arrow F represents the electrostatic force exerted on sphere B by sphere A.

F

Net force equation

Net force =Fnet = masse x acceleration

Newton's second law

The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.

Which body is in equilibrium?

a block sliding at constant velocity across a table- top

A man standing on a scale in an elevator notices that the scale reads 30 newtons greater than his normal weight. Which type of movement of the elevator could cause this greater-than-normal reading?

accelerating upward

the e diagram shows a worker using a rope to pull a cart. e worker's pull on the handle of the cart can best be described as

both magnitude and direction

A 6.0-newton force and an 8.0-newton force act concurrently on a point. As the angle between these forces increases from 0° to 90°, the magnitude of their resultant

decreases

As angle θ is increased, the horizontal acceleration of the mass

decreases

As a constant unbalanced force acts on an object in the direction of motion, the object's speed

increases

When the index card is quickly pulled away from the glass in a horizontal direction, the disk falls straight down into the glass. is action is a result of the disk's

inertia

A box is pushed toward the right across a classroom oor. e force of friction on the box is directed toward the

left

A student is standing in an elevator that is accelerat- ing downward. e force that the student exerts on the oor of the elevator must be

less than the weight of the student when at rest

Newton's third law

ll forces between two objects exist in equal magnitude and opposite direction: if one object A exerts a force FA on a second object B, then B simultaneously exerts a force FB on A, and the two forces are equal in magnitude and opposite in direction: FA = −FB.

if the sum of all the forces acting on a moving object is zero, the object will

ontinue moving with constant velocity

The string is cut and the carts move apart. Compared to the magnitude of the force the spring exerts on cart A, the magnitude of the force the spring exerts on cart B is

same

Which graph best represents the motion of an object in equilibrium?

the graph where displace and time are a linear line

A constant unbalanced force is applied to an object for a period of time. Which graph best represents the ac- celeration of the object as a function of elapsed time?

the graph with the straight line

A baseball bat moving at high velocity strikes a feather. If air resistance is neglected, compared to the force exerted by the bat on the feather, the force exerted by the feather on the bat will be

the same

A 0.50-kilogram cart is rolling at a speed of 0.40 meter per second. If the speed of the cart is doubled, the inertia of the cart is

unchanged