Unit 1 Forces and Motion – Flashcards (English)

Flashcards covering net velocity, net forces, force concepts, force diagrams, and related topics from the provided notes.

What is the net velocity of the airplane traveling east at 90 m/s with a headwind of 5 m/s from the west?

85 m/s East.

What is the net velocity of Person A walking 1 m/s east on a walkway moving 2 m/s east?

3 m/s East.

What is the net velocity of Person B walking 3 m/s west on a walkway moving 2 m/s east?

1 m/s West.

What is the net force when a car is pushed with 800 N to the left and experiences a frictional force of 700 N?

100 N Left.

In tug-of-war, if red team pulls 2000 N to the left and blue team pulls 1500 N to the right, what is the net force?

500 N to the Left.

What is a force in science?

A push or pull exerted on an object.

What unit is used to measure force?

Newton (N).

What does the net force tell you about an object's motion?

If net force is zero, the object has no acceleration; if nonzero, it accelerates in the direction of the stronger force.

What is a force diagram?

A visual model of the forces acting on an object, shown as arrows with direction and magnitude.

What is the difference between speed and velocity?

Speed is how fast an object moves; velocity includes both speed and direction.

What does the sign of velocity indicate?

Direction along a chosen axis; positive or negative based on that direction.

What is acceleration?

The rate at which velocity changes over time.

How can forces change velocity when a bus speeds up, slows down, or turns?

They cause a change in velocity, i.e., acceleration, which can be in speed or direction.

How do you find a person’s velocity relative to the ground when on a moving walkway?

Add the velocity of the person relative to the walkway to the velocity of the walkway relative to the ground (vector addition).

What is a contact force?

A force that acts between objects that are touching (e.g., push, pull, friction).

What is a noncontact force?

A force that can act at a distance (e.g., gravity, magnetic, electric).

What forces act on a rocket in a force diagram?

Gravity acting downward and thrust acting upward.

What forces act on a paper airplane in flight?

Gravity, lift, thrust, and air resistance (drag).

If two forces act in the same direction (e.g., 20 N and 30 N to the right), what is the net force?

50 N to the right.

If two equal forces act in opposite directions (e.g., 20 N right and 20 N left), what is the net force?

0 N; the forces are balanced.

Why might a train need more than one locomotive?

To provide enough forward thrust to move a very heavy train, especially uphill, overcoming weight and friction.

What factor can affect the strength of the force needed to push a lawn mower?

Length of the grass (and resistance) can affect the required force.