Quiz 1 for physics

Suppose that critters are discovered on Mars who measure distance in boogles and time in bops. What would the units of velocity be?

Velocity has the same units as speed, so it will also be measured in boogles/bops.

Which one of the following are examples of vector quantities?

Velocity, displacement, force, and acceleration.

What is a scalar quantity?

A scalar has only magnitude.

What is a vector quantity?

A vector quantity has both magnitude and direction.

A ball tied to a string fastened at the other end to a rigid support forms a pendulum. If we pull the ball to one side and release it, the ball moves back and forth along an arc determined by the string length. What happens to the speed when the ball reverses direction?

At the turn-around points the speed is zero.

Suppose a graph of displacement of a body versus time is constructed. The slope of the graph at any point may be identified with:

instantaneous velocity.

Which of the following quantities relating to motion is not a scalar?

velocity

A car is driven between two nearby towns at an average speed of 50 km/hr. The magnitude of the average velocity of the car:

will be the same as or less than the average speed.

study graphs

#9,10,11,12,13,14,24

A ball tied to a string fastened at the other end to a rigid support forms a pendulum. If we pull the ball to one side and release it, the ball moves back and forth along an arc determined by the string length. Explain if the velocity is constant.

The velocity changes because its magnitude and direction of the ball are changing.

Which of the following quantities relating to motion is not a vector?

Speed

Suppose a graph of velocity of a body versus time is constructed. The slope of the graph at any point may be identified with:

instantaneous acceleration.

A car rolls down an incline starting from rest. A graph of position versus time is made for this motion. One can get the:

instantaneous velocity from the slope of the graph.

The following quantities relate to the rate of change of position. Which pair will always have the same magnitude?

Instantaneous speed and instantaneous velocity.

A ball tied to a string fastened at the other end to a rigid support forms a pendulum. If we pull the ball to one side and release it, the ball moves back and forth along an arc determined by the string length. Is the speed likely to be constant in this process?

No

A ball tied to a string fastened at the other end to a rigid support forms a pendulum. If we pull the ball to one side and release it, the ball moves back and forth along an arc determined by the string length. Is the velocity constant in this process?

No

Which one of the following are examples of scalar quantities?

Speed, distance, time, energy, mass, and temperature.

A dropped ball gains speed as it falls. Can the velocity of the ball be constant in this process?

When a ball is dropped it moves in a constant direction (downwards), but the magnitude of its velocity (speed) increases as it accelerates due to gravity.

A ball attached to a string is whirled in a horizontal circle such that it moves with constant speed. Does the velocity of the ball change in the process?

Yes, the velocity is not constant although the speed is constant. The velocity is not constant since its direction changes.

A ball is thrown against a wall and bounces back toward the thrower with the same speed as it had before hitting the wall. Does the velocity of the ball change in this process?

Yes, when the ball bounces back from the wall, the direction of its velocity is different than when it approaches the wall.

A student plots data for the velocity of a body versus the time on a graph. The area under the curve on the graph may be identified as:

displacement.