Physics Midterm Study Guide

Mrs. Cohen

Velocity

a change in position over time

Acceleration

change in an objects velocity

Force

Push or Pull that tends to accelerate an object

Vector

A quantity that had both magnitude and direction

Position

The distance in some direction from a reference point

Distance

The total amount of ground covered by an object (no direction)

Displacement

Change in position; difference between an objects final and initial position

Speed

How fast an object moves (no direction)

Mass

A measurement of how much matter is in an object

Weight

The force acting on the object due to acceleration or gravity (measured in Newtons)

Friction

A push or pull that tends to accelerate an object

What is the difference between distance and displacement?

Displacement has direction; distance does not

When are distance and displacement the same?

Only if direction does not change

What is the difference between speed and velocity?

Velocity has direction; speed does not

An object is accelerating upward. Describe what is happening to the object displacement with each passing second.

Displacement is becoming more positive with each second

How is acceleration related to velocity for an object speeding up?

Velocity and Acceleration in same direction

How is acceleration related to velocity for an object slowing down?

Velocity and Acceleration in opposite directions

What does a position vs. time graph represent?

represents Velocity

What does a velocity vs. time graph represent?

represents Acceleration

What is the magnitude and direction of acceleration for an object in freefall?

downwards -9.81 m/s²

Two objects with different masses are dropped from the same height. Assuming air resistance is negligible, which will hit the ground first?

Both objects will hit the ground at the same time (mass does not effect the rate at which they fall)

An object is tossed in the air, what is happening to the velocity as the object is traveling upward?

Velocity is decreasing

An object is tossed in the air, at its highest point what is the object’s velocity?

Velocity is zero

An object is tossed in the air, on the way down what is happening to the objects velocity

Velocity is increasing (in the negative direction)

What does the length of a vector arrow represent?

The magnitude of a vector

What is a projectile?

A launched object allowed to fall/fly freely

A projectiles horizontal velocity?

Vox = Vx

A projectiles vertical velocity?

Vy = Ayt + Voy (a= -9.81m²)

A projectiles horizonal acceleration?

Ax = 0 m/s²

A projectiles vertical acceleration?

Ay = -9.81m/s²

For a projectile launched at an angle. describe the velocity at the peak of flight?

At peak velocity is zero (Vy = 0m/s; Vx = Vox)

What is weight? How is it related to mass?

The force acting on the object due to acceleration or gravity

F = mg

Describe the normal force exerted on an object.

Force that prevents objects from passing through one another

Is normal force always equal to weight?

Not always; not for objects on inclined surfaces or pulled at an angle.

How is force related to mass and acceleration?

F= ma — Newtons Second Law states that the acceleration of an objects is directly related to net force and inversely related to its mass

Describe that state of equilibrium in term of net force and acceleration.

Fnet = 0N

Can an object in equilibrium be moving?

Yes, at constant velocity

Describe Newton’s first law

An object will not change motion unless acted upon

What is inertia and how does it relate to mass?

Inertia is the resistance of an object to changes in its state of motion. It is directly related to an object's mass. The greater the mass of an object, the greater its inertia. In other words, objects with more mass require more force to accelerate or decelerate compared to objects with less mass.

Describe Newton’s second law

F=ma

What causes acceleration?

Fnet is not zero

Describe Newton’s third law

Forces acting in pairs