Work and Simple Machines

A player pushes a 250 g hockey puck with a force to accelerate it at 24 m/s² over 0.50 m. How much work is done?

• 1.5 J

• 3.0 J

• 4.0 J

• 5.2 J

You push a book with a force of 4.6 N across a table for 0.60 m. What's the work done?

• 2.76 J

• 7.5 J

• 1.8 J

• 5.6 J

How much work is done when lifting a 25 kg bag of sand to a height of 1.1 m?

• 175 J

• 220 J

• 270 J

• 300 J

A pulley system lifts a 30 kg carton 15.3 m with 211 N over 28.0 m. What's the mechanical advantage (MA)?

• 2.0

• 1.3

• 3.0

• 1.6

If a machine has an MA of 3.5 and you apply 400 N, what's the max weight it can lift?

• 1000 N

• 1200 N

• 1400 N

• 1500 N

A lever lifts a crate 5.0 cm while the user applies force over 80.0 cm. What’s the efficiency if MA = 3.5?

• 10%

• 50%

• 75%

• 6.25%

A worker pushes a lawn mower with 23.0 N at 60° for 18.5 m at 1.25 m/s. What is the power?

• 100 W

• 135 W

• 90 W

• 80 W

Hoover Dam generates 2.0 × 10⁶ kW of power daily. How much work is done in one day?

• 1.7 × 10¹¹ J

• 2.4 × 10¹¹ J

• 1.8 × 10¹² J

• 1.7 × 10¹³ J

A 10 kg box is lifted to a height of 2 m in 5 seconds. What is the power used?

• 20 W

• 39 W

• 50 W

• 200 W

What is the work done by a force of 100 N applied at an angle of 45° across 10 m?

• 707 J

• 1000 J

• 500 J

• 1414 J