20 J of gravitational potential energy is lost when an object falls 5 m. What is the mass of the object?

How does a circuit breaker protect a refrigerator? a. when the current is too high, a metal strip in the fuse melts and opens the circuit. b. when the resistance is too high , a re-settable which opens a circuit c. when the current is too high , a re-settable switch opens the circuit d. when the resistance is too high a metal strip in the fuse melts and opens the circuit

Acar jack with a mechanical advantage of 6 needs to produce an output force of 600 n to raise a car. what input force is required? 6 n 100 n 600 n 3,600 n

Ineed to answer this problem but i lack in knowledge, what should i study to answer this problem? i have never used derivatives in a physics problem so i'm not sure what's happening and i can't find videos explaining.