20 questions
A rightward force is applied to a crate to push it across the floor at a constant speed. | |||
A rightward force is applied to a dresser to accelerate it to the right across the bedroom floor. | |||
A rightward-moving car is skidding to a stop across a level roadway with locked wheels. | |||
A football is moving upward and rightward towards the peak of its trajectory. Ignore air resistance. | |||
A small elevator is secured to a motor by a cable and is moving upward with constant speed. |
A hockey puck glides to the right across the ice at a constant speed. | |||
A downward-moving skydiver who has just opened the parachute is slowing down. | |||
A sledder is coasting to the left while slowing down along the loosely-packed snow. | |||
A softball player does a head-first dive and is sliding to the right across the infield dirt. | |||
A football, originally kicked at an 40-degree angle, is at the peak of its trajectory. |
What is the net force?
40 N left
0 N Balanced
400 N right
40 N right
How will motion change?
It will not accelerate.
It will accelerate to the right.
It will accelerate to the left.
It will accelerate upward.
You and your dad are moving the couch from one side of a room to another. Your dad pushes with a force of 35 N to the right and you push with a force of 25 N right. What is the net force on the couch?
60 N right
10 N left
60 N left
50 N right
Object's tendency to resist change
Friction
Inertia
Force
Gravity
A car is driving on the road when a fly hits the window. In this situation:
The force exerted on the car by the fly is less than the force exerted by the fly on the car.
The force exerted on the car by the fly is equal to the force exerted by the fly on the car.
The force exerted on the car by the fly is greater than the force exerted by the fly on the car.
The fly does not exert a force on the car.
The car does not exert a force on the fly.
An elevator is traveling upward in an elevator shaft at a constant speed. Assume that all friction effects are negligible. According to this situation, the forces on the elevator are best described by the following:
The upward force is greater than the downward force due to gravity.
The upward force is equal to the downward force due to gravity.
The upward force is less than the downward force due to gravity.
The upward force is greater than the sum of the downward force due to gravity and air resistance.
The upward force is less than the sum of the downward force due to gravity and air resistance.
A ball is launched from rest in outer space. Assume all outside forces other than the launch force are negligible. Three seconds after the ball has been launched, which of the following is true?
The ball is accelerating in the direction of motion due to the launch force.
The ball is accelerating in the direction opposite motion due to the launch force.
The ball accelerates in the direction of motion initially and then moves with constant velocity.
The ball accelerates in the direction opposite motion initially and then moves with constant velocity.
The ball is not accelerating and moves with constant velocity.
A person stands on a scale in order to weigh herself. The diagram below shows two possible forces acting on her. Which of the following is the correct description of the forces acting on her?
the force exerted by the scale is greater than the force due to gravity on her
the force exerted by the scale is equal to the force due to gravity on her
the force exerted by the scale is less than the force due to gravity on her
only the force due to gravity exists
only the force exerted by the scale exists
Suppose a particle is accelerated through space by a constant 10-N force. Suddenly the particle encounters a second force of 10-N in a direction opposite to that of the first force. The particle
is brought to a rapid halt.
theoretically accelerates to speeds approaching the speed of light.
continues at the speed it had when it encountered the second force.
gradually decelerates to a halt.
none of the above
A car slides across an icy road in a straight line at a constant speed until it hits pavement. Which of Newton's Laws is most applicable when describing why this happens?
Newton's First Law (Inertia)
Newton's Second Law (F = ma)
Newton's Third Law (Action-Reaction)
Newton's Law of Universal Gravitation
Newtons ___________ says any force exerted by object A onto object B will produce a force from object B onto object A
First Law (Inertia)
Second Law (F = ma)
Third Law (Action-Reaction)
Law of Universal Gravitation
Newton's __________________ says that the Net Force on an object is directly related to the objects acceleration.
First Law (Inertia)
Second Law (ΣF = ma)
Third Law (Action-Reaction)
Law of Universal Gravitation
A plane is traveling East encounters a wind traveling West that exerts a force on the plane. The plane will
speed up
slow down
remin at a constant speed
change direction
A 10 kg dog weighs
100 Newtons
1.00 Newtons
50 Newtons
200 Newtons
A skydiver falls downward at a constant speed. What can we say about the forces acting on them?
weight is larger than air resistance
air resistance is larger than weight
air resistance is equal to weight
gravitational force is greater than weight
A rock that weighs 75 N is dropped from a building and falls downwards through the air. Air resistance exerts a force of 50 Newtons upwards. The rock will
accelerate downwards and speed up
accelerate downwards and slow down
acceleration upwards and speed up
accelerate upwards and slow down
Which condition must be true in order for a system to be moving at a constant speed (no acceleration)?
The system has no weight
The forces on the system are unbalanced
There are no forces acting on the system
The net force is equal to zero