AP Physics 1 Forces

Apollo 13 is a 1995 movie about a mission to the Moon that experiences serious problems. In the movie, an astronaut says, “We just put Sir Isaac Newton in the driver’s seat.” This line, a reference to Newton’s First Law, is spoken just after

• the rocket begins firing its engines and lifts off from the launch pad.

• the spacecraft begins firing its engines on its way back to Earth from the Moon.

• the spacecraft enters Earth’s atmosphere and air resistance begins to slow its descent.

• the spacecraft has finished firing its engines and has spent all of its fuel.

An aircraft flying to the right has a constant horizontal speed of 200 m/s has four forces acting on it shown above left. When the aircraft passes through the cloud at point S (shown above right), the force of thrust has the same magnitude as the force of drag, and the force of lift balances the force of weight. If this condition continues, which path shown above right will the plane follow?

• A

• B

• C

• D

• E

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NGSS.HS-PS2-1

A skydiver falling through the air opens her parachute. The skydiver and parachute together have a weight W. At a specific instant after the parachute opens, the force of air resistance on the parachute is 1.4W. What is the acceleration of the parachute-and-skydiver system at this instant?

• 14 m/s² downward

• 4 m/s² downward

• 4 m/s² upward

• 14 m/s² upward

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NGSS.HS-PS2-1

A student hypothesizes that a certain elastic cord exerts a constant force even as the cord contracts to its natural length. To test this hypothesis, the student attaches the cord to a cart and stretches the cord a significant distance. The student releases the cart and measures the increase in speed Δv of the cart during an interval of time Δt. If the student performs multiple trials in which the mass M of the cart is varied, which of the following graphs would yield a line if the cord’s force were constant?

• M vs. (Δv/Δt)

• M vs. (Δt/Δv)

• M² vs. (Δv/Δt)

• M2 vs. (Δt/Δv)

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NGSS.HS-PS2-1

A car travels up a hill at constant speed. Which of the following diagrams best represents the forces acting on the car at this instant?

• 
• 
• 
• 

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NGSS.HS-PS2-1

Three forces of equal magnitude act on the box shown. One force is upward, one downward, and one rightward. Which of the following statements must be true based on this information? Select two answers.

• The box must have a rightward component of velocity.

• The box has no vertical component of velocity.

• The acceleration of the box is directed to the right.

• The velocity of the box is changing with time.

Tags

NGSS.HS-PS2-1