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.