Newton's Laws
The force required to accelerate a 2.0-kilogram mass at 4.0 meters per second2 is ______
8 N
Compared to the force needed to start sliding a crate across a rough level floor, the force needed to keep it sliding once it is moving is ________.
less
A 65.0-kilogram astronaut weighs 638 newtons at the surface of Earth. What is the mass of the astronaut at the surface of the Moon, where the acceleration due to gravity is 1.62 meters per second squared?
65 kg
Double Jeopardy: Two students are pushing a car. What should be the angle of each student’s arms with respect to the flat ground to maximize the horizontal component of the force?
A) 0º
B) 30º
C) 45º
D) 90º
A) 0 degrees
A 12.0-kilogram cart is moving at a speed of 0.25 meter per second. After the speed of the cart is tripled, the inertia of the cart will be
(A) unchanged
(B) one-third as great
C) three times greater
D) nine times greater
A) unchanged
A 30-kilogram boy exerts a force of 100 Newtons on a 50-kilogram object. The force that the object exerts on the boy is
-100 N
Double Jeopardy: What is the magnitude of the force needed to keep a 60.-newton rubber block moving across level, dry asphalt in a straight line at a constant speed of 2.0 meters per second?
40 N
At a certain location, a gravitational force with a magnitude of 350 newtons acts on a 70.-kilogram astronaut. What is the magnitude of the gravitational field strength at this location?
5.0 N/kg or 5 m/s/s
A child pulls a wagon at a constant velocity along a level sidewalk. The child does this by applying a 22-newton force to the wagon handle, which is inclined at 35° to the sidewalk (Note to Rodelli: Draw the picture on the board).
What is the magnitude of the force of friction on the wagon?
18 N
If a block is in equilibrium, the magnitude of the block's acceleration is
A) zero
B) decreasing
C) increasing
D) constant, but not zero
A) zero
A 25-newton horizontal force northward and a 35-newton horizontal force southward act concurrently on a 15-kilogram object on a frictionless surface. What is the magnitude of the object's acceleration?
0.67 m/s/s
What is the magnitude of the minimum horizontal force needed to start a 300. kilogram steel block on a steel table in motion?
2220 N
A student is standing in an elevator that is accelerating downward. The force that the student exerts on the floor of the elevator must be
A) less than the weight of the student when at rest
B) greater than the weight of the student when at rest
C) less than the force of the floor on the student
D) greater than the force of the floor on the student
A) less than the weight of the student when at rest (acceleration is down so downward force of gravity must be larger than upward normal force)
The diagram (drawn on board) shows a person exerting a 300.-newton force on the handle of a shovel that makes an angle of 60.° with the horizontal ground.
The component of the 300.-newton force that acts perpendicular to the ground is approximately ______
260 N
A 15-kilogram cart is at rest on a horizontal surface. A 5-kilogram box is placed in the cart. Compared to the mass and inertia of the cart, the cart-box system has
A) less mass and more inertia
B) more mass and the same inertia
C) the same mass and more inertia
D) more mass and more inertia
D) more mass and more inertia