Physics Unit 8 Review: Work and Power

Lamar Gant, U.S. powerlifting star, became the first man to deadlift five times his own body weight in 1985. Deadlifting involves raising a loaded barbell from the floor to a position above the head with outstretched arms. Determine the work done by Lamar in deadlifting 300 kg to a height of 0.90 m above the ground (W=Fd).

• 270 J
• 2646 J
• 333 J
• 3.00X10^-3 J

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NGSS.MS-PS3-5

What is the equation for mechanical advantage?

• MA=input force*output force
• MA=output force/input force
• MA=input force/output force
• MA= output force - input force

Is this an example of work?
A teacher applies a force to a wall and becomes exhausted.

• True
• False

If a lion drags his prey 10 meters to his den doing 500 joules of work, how much force did he use?

• 50 Newtons
• 500 Joules
• 50,000 Newtons
• 10 Newtons

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NGSS.MS-PS2-2

Work is done on an object when an applied force causes the object to move in the same direction as the force.

• agree

• disagree

How much work is done against gravity lifting a 2 kg-sack of groceries a distance of 2.5 meters?

• 24.4N

• 5N

• 19.6N

• 49N

A machine exerts a force of 300 N to push a box 30.0 m horizontally in 3.00 s. Calculate the power of the machine.

• 27000 W

• 100 W

• 10 W

• 3000 W

Which object has the most amount of work done on it?

• W

• X

• Y

• Z

Tags

NGSS.MS-PS3-5

How much work is done in holding a 15 N sack of potatoes while waiting in line at the grocery store for 3 minutes?

• 15 J
• 45 J
• 0 J
• 5 J

ln the Empire State Building Run-Up, competitors race up the 1576 steps (86 flights) of the Empire State Building, climbing a total vertical distance of 320 m. How much work does a m 74 kg racer do?

• 2.321 × 10⁵ Joules

• 2.326 × 10⁵ Joules

• 2.318 × 10⁵ Joules

• 2.317 × 10⁵ Joules

Tags

NGSS.MS-PS2-2