Work

In physics, work is calculated or measured as _______________________________________.

• Force times time (F×t)

• Force divided by time (F/t)

•  Force times distance (F×d)

• Force divided by distance (F/d)phywork

Which of the following is NOT an example of work?

• Sliding a 450 Newton crate across the floor for 20 meters

• Holding a 750 Newton barbell overhead for 10 minutes

• Lifting a 200 Newton stereo 2 meters into the back of a truck

• Pushing a lawnmower across the yard for 50 meters

Tags

NGSS.MS-PS3-5

You carry a backpack for one mile. You then carry the same backpack for two miles. Compared to the one mile hike, how much work have you done?

• Four times as much

• Twice as much

• The same amount

• One half as much

You carry a backpack for one mile. You then carry the same backpack for two miles. Compared to the one mile hike, how much work have you done?

• 2J

• 5J

• 10J

• 50J

Power is defined as the __________________________________________________________.

• Force on an object times the distance the object moves (F×d)

• Force on an object divided by the time the force acts (F/t)

• Work done on an object divided by the time taken to do the work (W/t)

• Work done on an object times the time it takes to do that work (W×t)

Tags

NGSS.MS-PS3-4

A job is done slowly, and an identical job is done quickly. Both jobs require the same amount of work, but different amounts of ____________________.

• Energy

• Power

• Both

• None

How much power is required to do 100 J of work on an object in 2 seconds?

• 200 W

• 100 W

• 50 W

• 2 W

Kinetic energy of an object is equal to __________________________________________________.

• One half the product of its mass times its speed squared (½mv2)

• One half the product of its mass times its speed (½mv)

• Its mass multiplied by its speed

  (m × v)

• Its mass multiplied by its acceleration (m × a)

Tags

NGSS.MS-PS3-1

What is the kinetic energy of a bowling ball with a mass of 3 kg moving down the lane with a velocity of 2.5 m/s?

• 3.75 Joules

• 18.75 Joules

• 73.57 Joules

• 9.375 Joules

Tags

NGSS.MS-PS3-1

Which has more kinetic energy: a car sitting still or a person jogging at 10 m/s?

• The car

• The jogger

• They have the same amount of kinetic energy

• Not enough information to tell

Tags

NGSS.MS-PS3-1