In this worksheet, we will practice applying Newton's second law of motion to define gravitational field strength as the force acting on an object per kilogram of its mass.

**Q3: **

A chair has a mass of 50 kg. What force does the chair’s weight apply to the ground below it?

- A 9.8 N
- B 50 N
- C 560 N
- D 490 N
- E 500 N

**Q4: **

An astronaut on Earth, where the gravitational field strength is 9.8 N/kg, has a mass of 65 kg and a weight of 637 N. The astronaut is sent to a space station, where the gravitational field strength is 9.5 N/kg.

What is the astronaut’s mass on the space station?

What is the astronaut’s weight on the space station?

**Q5: **

An astronaut who has a mass of 81.25 kg goes to the Moon, where the acceleration due to gravity is 1.6 m/s^{2}. What force does
the astronaut’s weight apply to the lunar surface beneath the astronaut’s feet?

**Q6: **

An astronaut who has a mass of 80 kg goes to Mars. On Mars, the astronaut applies a force of 296 N to the ground beneath her due to her weight. What is the acceleration due to gravity at the surface of Mars?

**Q7: **

The gravitational field strength of a planet becomes weaker as the distance from the planet’s surface increases. Several thousand kilometers above a planet, its gravitational field strength is 2.4 N/kg. What force, in kilonewtons, toward the planet’s surface is experienced by a spacecraft with a mass of 25 000 kg?