A student claims that hitting a tennis ball across the court is an example of balanced forces. Is he correct?(1 point)
Responses
Yes, because the force in the direction of the ball’s motion is greater.
Yes, because the force in the direction of the ball’s motion is greater.
No, because equal forces act on the ball from all sides.
No, because equal forces act on the ball from all sides.
No, because the force in the direction of the ball’s motion is greater.
No, because the force in the direction of the ball’s motion is greater.
Yes, because equal forces act on the ball from all sides.
No, because equal forces act on the ball from all sides.
No, because equal forces act on the ball from all sides.
The correct answer is: No, because equal forces act on the ball from all sides.
To understand why this is the correct answer, let's first review what balanced forces mean. Balanced forces refer to a situation where all the forces acting on an object are equal in magnitude and opposite in direction. As a result, the object remains at a constant velocity or remains at rest.
In the case of hitting a tennis ball across the court, the forces acting on the ball are not balanced. When you hit the ball, you apply a force in one direction to accelerate it. However, the ball also experiences an equal and opposite force from the air resistance and friction with the ground. These forces act in the opposite direction of the ball's motion and prevent it from continuing to move indefinitely in one direction.
Therefore, the student's claim that hitting the tennis ball across the court is an example of balanced forces is incorrect. The forces acting on the ball are not balanced because there are equal forces acting on the ball from all sides.
A student is moving boxes. Box A and box B are the same size and shape . The student can lift box A, but not box B. What is the difference between the boxes?(1 point)
Responses
Box B has more mass and takes more friction to lift.
Box B has more mass and takes more friction to lift.
Box B has more mass and takes more force to lift.
Box B has more mass and takes more force to lift.
Box B has more mass and takes less force to lift.
Box B has more mass and takes less force to lift.
Box A has more mass and takes less friction to lift.
Box B has more mass and takes more force to lift.
Why is a book resting on a table in a state of equilibrium?(1 point)
Responses
The book’s weight and the upward force the table exerts on the book have equal magnitude but opposing directions.
The book’s weight and the upward force the table exerts on the book have equal magnitude but opposing directions.
The book and the table have the same weight.
The book and the table have the same weight.
The book and the table both have acceleration (due to gravity) of 9.8 m/s/s.
The book and the table both have acceleration (due to gravity) of 9.8 m/s/s.
Gravity is a net force acting on the book in a downward direction.
The book’s weight and the upward force the table exerts on the book have equal magnitude but opposing directions.
The spacecraft shown below weighs 6.1 million pounds. The rocket produces 7.5 million pounds of thrust.
When the spacecraft falls back to earth, a parachute helps it fall safely. Explain the forces acting during this landing.
(1 point)
Responses
The parachute’s downward force resists gravity’s upward force.
The parachute’s downward force resists gravity’s upward force.
The parachute’s downward force resists gravity’s downward force.
The parachute’s downward force resists gravity’s downward force.
The parachute’s upward force resists gravity’s downward force.
The parachute’s upward force resists gravity’s downward force.
The parachute’s upward force resists gravity’s upward force.
The parachute’s upward force resists gravity’s downward force.
A student walks east 100 meters in 2 minutes. She then walks north 200 meters in 4 minutes. Which statement is true?(1 point)
Responses
Her velocity changes because her speed varies.
Her velocity changes because her speed varies.
Her velocity is constant because her direction is constant.
Her velocity is constant because her direction is constant.
Her velocity changes because her direction changes.
Her velocity changes because her direction changes.
Her velocity is constant because her speed is constant.
Her velocity changes because her direction changes.
Hector went to the music store by heading due south at 3 m/s, then turning West and continuing at the same speed for another three blocks. Which of the following is true about Hector's velocity?(1 point)
Responses
Hector's velocity changed because his speed changed.
Hector's velocity changed because his speed changed.
Hector's velocity changed because his direction changed.
Hector's velocity changed because his direction changed.
Hector's velocity did not change because his speed did not change.
Hector's velocity did not change because his speed did not change.
Hector's velocity did not change because his direction did not change.
Hector's velocity changed because his direction changed.
A car that is traveling west at a constant rate has(1 point)
Responses
acceleration and speed, but no velocity.
acceleration and speed, but no velocity.
velocity, but neither acceleration nor speed.
velocity, but neither acceleration nor speed.
speed, but neither velocity nor acceleration.
speed, but neither velocity nor acceleration.
speed and velocity, but no acceleration.
speed and velocity, but no acceleration.
A student is investigating mass and acceleration. The student applies the same force to two boxes, as shown in the table.
The student claims that box 1 must have a smaller mass than box 2. Which argument best supports the student's claim?(1 point)
Responses
Heavier objects need greater force than lighter objects to accelerate at the same rate.
Heavier objects need greater force than lighter objects to accelerate at the same rate.
Lighter objects need less force than heavier objects to start moving but will accelerate at the same rate.
Lighter objects need less force than heavier objects to start moving but will accelerate at the same rate.
Lighter objects need greater force than heavier objects to start moving but will accelerate at the same rate.
Lighter objects need greater force than heavier objects to start moving but will accelerate at the same rate.
Heavier objects need less force than lighter objects to accelerate at the same rate.
The argument that best supports the student's claim is: "Heavier objects need greater force than lighter objects to accelerate at the same rate."
While playing her soccer game, Samantha runs down the field at 10 meters per second. She has a constant speed and does not change direction. What is Samantha’s acceleration?(1 point)
Responses
The acceleration is 0 m/s^2 because her velocity increased.
The acceleration is 0 m/s^2 because her velocity increased.
The acceleration is 10 m/s^2 because her velocity did not change.
The acceleration is 10 m/s^2 because her velocity did not change.
The acceleration is 0 m/s^2 because her velocity did not change.
The acceleration is 0 m/s^2 because her velocity did not change.
The acceleration is 10 m/s^2 because her velocity increased.
The acceleration is 0 m/s^2 because her velocity did not change.
Two forces act on an object. One force has a magnitude of 10 N directed north, and the other force has a magnitude of 2 N directed south. What is the net force on the object?(1 point)
Responses
8 N south
8 N south
25 N north
25 N north
8 N north
8 N north
12 N south
The net force on the object is 8 N north.
To determine the net force, we need to subtract the force directed south (2 N) from the force directed north (10 N).
10 N north - 2 N south = 8 N north
An object at rest remains at rest. An object in motion remains in motion unless acted upon by an outside force. This describes which of Newton’s Laws of Motion?(1 point)
Responses
First Law of Motion
First Law of Motion
First and Third Laws of Motion
First and Third Laws of Motion
Second and Third Laws of Motion
Second and Third Laws of Motion
Second Law of Motion
Second Law of Motion
First Law of Motion
Suppose 25 children who weigh the same are playing a game of tug-of-war. Five children pull with 10 newtons of force, while ten children pull with 15 newtons of force in the opposite direction. How can one determine the net force on the rope?(1 point)
Responses
The forces are in the same direction, so the newtons can be added.
The forces are in the same direction, so the newtons can be added.
The forces are in opposite directions, so the newtons can be divided.
The forces are in opposite directions, so the newtons can be divided.
The newtons are in the same direction, so the newtons can be multiplied.
The newtons are in the same direction, so the newtons can be multiplied.
The forces are in opposite directions, so the newtons can be subtracted.
The forces are in opposite directions, so the newtons can be subtracted.
To measure average speed, what data is required?(1 point)
Responses
The weight of the bike and the time spent
The weight of the bike and the time spent
The direction and the distance of travel
The direction and the distance of travel
The distance traveled and the time spent
The distance traveled and the time spent
The direction of travel and the weight of the bike
The distance traveled and the time spent
Speed, unlike acceleration or velocity, does NOT specify _______.(1 point)
Responses
Distance
Distance
Mass
Mass
Time
Time
Direction