Force and Work Review

What is the unit of force?

• Joule

• Newton

• Watt

• Pascal

Answer explanation

The unit of force is the Newton, named after Sir Isaac Newton. It is defined as the force required to accelerate a one-kilogram mass by one meter per second squared. Joule, Watt, and Pascal are units of energy, power, and pressure, respectively.

What is the unit of work?

• Newton

• Joule

• Pascal

• Watt

Answer explanation

The unit of work is the Joule, which measures energy transfer when a force is applied over a distance. Newton measures force, Pascal measures pressure, and Watt measures power, making Joule the correct choice for work.

Tags

NGSS.HS-PS2-1

What must happen for an object to be considered as having done work?

• It must be displaced

• It must be stationary

• It must be heavy

• It must be light

Answer explanation

For an object to be considered as having done work, it must be displaced. Work is defined as the transfer of energy that occurs when an object is moved by a force over a distance.

Tags

NGSS.MS-PS3-5

What is the distance between the starting point of an object and its ending point called?

• Displacement

• Velocity

• Acceleration

• Momentum

Answer explanation

The distance between the starting point and ending point of an object is called displacement. It measures the shortest path between two points, considering direction, unlike distance which is scalar.

A player kicks a soccer ball with 1.2N of force, causing it to travel 0.15 meters. What amount of work does the player do on the ball?

• 0.18 joules

• 1.35 joules

• 0.12 joules

• 1.5 joules

Answer explanation

Work is calculated using the formula: Work = Force x Distance. Here, Work = 1.2N x 0.15m = 0.18 joules. Thus, the correct answer is 0.18 joules.

Tags

NGSS.MS-PS3-5

What is a joule defined as in terms of force and distance?

• 1 N x 1 m

• 1 kg x 1 m

• 1 N x 1 s

• 1 kg x 1 s

Answer explanation

A joule is defined as the work done when a force of one newton moves an object one meter. Therefore, the correct choice is 1 N x 1 m.

Tags

NGSS.HS-PS2-1

What is a screw in terms of simple machines?

• A flat surface

• A nail with an inclined plane wrapped around it

• A curved surface

• A horizontal plane

Answer explanation

A screw is essentially a nail with an inclined plane wrapped around it, allowing it to convert rotational motion into linear motion, making it a type of simple machine used for fastening.

Which of the following is NOT a benefit of using an inclined plane?

• It reduces the force needed

• It increases the distance the object moves

• It changes the direction of the force

• It increases the weight of the object

Answer explanation

The correct choice is 'It increases the weight of the object' because an inclined plane does not change the weight of an object; it only helps in reducing the force needed to move it, increasing the distance, or changing the direction of the force.

What happens when a pulley system is used?

• More mechanical force is needed

• Less mechanical force is needed

• The load becomes heavier

• The load moves faster

Answer explanation

Using a pulley system reduces the amount of mechanical force needed to lift a load. This is because pulleys distribute the weight and allow for easier movement, making it less strenuous to lift heavy objects.

Tags

NGSS.MS-ETS1-1

What is the fixed point called where a lever pivots?

• Fulcrum

• Load

• Effort

• Pivot

Answer explanation

The fixed point where a lever pivots is called the fulcrum. It is the crucial point that allows the lever to balance and amplify force, distinguishing it from the load (the weight being moved) and effort (the force applied).