Physics Quiz

Which of the following is used to measure speed?

• meters

• seconds

• seconds per meter

• meters per second

Answer explanation

Speed is defined as the distance traveled over time. The correct unit for measuring speed is 'meters per second', which indicates how many meters are covered in one second.

A bird flies 50 meters in 10 seconds. What is its speed?

• 0.2 second per meter

• 0.2 meters per second

• 5 seconds per meter

• 5 meters per second

Answer explanation

To find the speed, divide the distance by time. Speed = 50 meters / 10 seconds = 5 meters per second. Thus, the correct answer is 5 meters per second.

A flat horizontal line on a distance-vs.-time motion graph shows

• increasing speed

• decreasing speed

• no speed

• acceleration

Answer explanation

A flat horizontal line on a distance-vs.-time graph indicates that the distance does not change over time, meaning there is no movement. Therefore, the correct answer is 'no speed'.

Carts of different masses are placed on a ramp at different heights. Which combination of features will have the greatest gravitational potential energy?

• low mass and low height

• low mass and high height

• high mass and high height

• high mass and low height

Answer explanation

Gravitational potential energy is calculated using the formula PE = mgh, where m is mass, g is the gravitational constant, and h is height. Therefore, the combination of high mass and high height maximizes potential energy.

A student wants to conduct an investigation to determine if there is a relationship between the speed a cart and the cart’s kinetic energy. They should

• keep all variables the same except the kinetic energy of the cart.

• keep all variables the same except the speed of the cart.

Answer explanation

To investigate the relationship between speed and kinetic energy, the student should vary the speed of the cart while keeping other variables constant. Kinetic energy depends on speed, so this approach will reveal their relationship.

Tags

NGSS.MS-PS3-1

Which has the greater effect on the kinetic energy of a moving object, doubling its mass or doubling its speed?

• doubling the object’s mass

• doubling the object’s speed

• doubling both have equal effects

• Neither

Answer explanation

Kinetic energy is given by the formula KE = 1/2 mv². Doubling the speed (v) increases KE by a factor of four (since (2v)² = 4v²), while doubling the mass (m) only doubles KE. Thus, doubling the object's speed has a greater effect.

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-4

If there is no net force acting on a moving object, it will

• continue moving at the same speed.

• continue moving in the same direction.

• continue moving at the same speed and in the same direction.

• eventually slow down and stop.

Answer explanation

If no net force acts on a moving object, it will not change its state of motion. Therefore, it will continue moving at the same speed and in the same direction, making the correct choice: continue moving at the same speed and in the same direction.

Tags

NGSS.HS-PS2-2

What does it take to change the direction or speed of an object?

• more than one force

• an unbalanced force

• a balanced force

• no force

Answer explanation

To change the direction or speed of an object, an unbalanced force is required. This force disrupts the state of equilibrium, allowing the object to accelerate or change direction.

Tags

NGSS.MS-PS2-2

A ball rolls across a smooth surface at a steady 0.5 m/s. What is its acceleration?

• 0 m/s²

• 9.8 m/s²

• 0.5 m/s²

• 2 m/s²

Answer explanation

The ball is rolling at a constant speed of 0.5 m/s, which means there is no change in its velocity. Therefore, its acceleration is 0 m/s², indicating no acceleration.

What is the force needed to accelerate a 10 kg object at 2 m/s²?

• 5 N

• 10 N

• 15 N

• 20 N

Answer explanation

To find the force, use Newton's second law: F = m * a. Here, m = 10 kg and a = 2 m/s². Thus, F = 10 kg * 2 m/s² = 20 N. Therefore, the correct answer is 20 N.

Tags

NGSS.MS-PS2-2