Forces and Friction

A rock on Earth has a mass of 750 kg and a weight of 7,350 N. If the rock is taken into outer space, how will its mass and weight be affected?

• The weight and mass will remain the same because they are not altered by the effects of gravity

• The weight will remain the same, but the mass will change because of the effects of gravity.

• The mass will be 76.5 kg, and the weight will increase because of the effects of gravity.

• The mass will be 750 kg, but the weight will decrease because of the effects of gravity.

The rover Spirit is a robotic probe that NASA has placed on Mars. The gravitational attraction of Mars is approximately 62% less than that of Earth. Compared to its measurements on Earth, on Mars the probe has

• the same weight and the same mass.

• a larger weight, but smaller mass.

• a smaller mass and larger weight

• a smaller weight and the same mass.

Galileo designed experiments in which objects with different masses were dropped from the same height. Regardless of the mass, the objects appeared to hit the ground at the same time. What did Galileo conclude from these studies?

• Acceleration due to gravity is independent of mass.

• An object falls faster than another object that has lower weight.

• The rate at which an object falls is inversely proportional to its mass.

• The weight of an object is independent of its mass.

There is a very slight change in gravity at the top of a mountain. Which property would MOST likely be less at the top of a mountain?

• mass

• weight

• body density

• body temperature

A Mars Rover has been sent to explore and relay data from Mars. Mars is less massive than Earth. When compared with Earth, which is the BEST comparison between the mass and the weight of the Rover on Mars?

• The mass is more on Mars and the weight is less.

• The weight is more on Mars and the mass is less.

• The weight is less on Mars and the mass is the same.

• The mass is less on Mars and the weight is the same.

An object has a weight of 10 kg on the surface of Earth. If the same object were transported to the surface of Mars, the object would have a weight of 3.8 kg. Which BEST explains why the weight of the object changed when transported from Earth to Mars?

• The density of the object is greater on Earth than it is on Mars.

• The volume of the object is greater on Earth than it is on Mars.

• Gravitational force is greater on Earth than it is on Mars.

• Atmospheric pressure is less on Earth than it is on Mars.

If the mass of an object on Earth is 18 grams, what would the mass of the same object be on the Moon?

• 0 grams

• 3 grams

• 9 grams

• 18 grams

What causes a free falling object to accelerate?

• inertia

• gravity

• initial speed

• initial direction

A student drops a bowling ball and an apple from a third-story window. Both objects hit the ground at the same time. From the experiment the student should conclude that

• the apple weighs more than the bowling ball.

• the bowling ball speeds up faster than the apple.

• more air friction is acting on the apple than on the bowling ball.

• gravity pulls on both objects, causing them to fall at the same rate.

Brad was studying how the force of gravity affects an object. Brad’s table shows the weight and mass of an object on Earth and the relative gravity on Planet X and Planet Y. Brad needed to calculate any change to the weight or mass of the object on the two other planets.

Earth: weight 100lbs.

mass 45kg

Planet X: half the gravity of Earth

Planet Y: twice the gravity of Earth

Which chart shows the correct calculations for weight and mass of the object on Planet X and Planet Y?

• Planet X: weight 100lbs mass 85 kg

  Planet Y: weight 100lbs mass 45 kg

• Planet X: weight 100lbs mass 22.5 kg

  Planet Y: weight 100lbs 90kg

• Planet X: weight 50lbs mass 45kg

  Planet Y: weight 200lbs mass 45kg

• Planet X: weight 100lbs mass 90kg

  Planet Y: weight 100lbs mass22.5 kg