# Basic Newtonian Problems #2

1. Oct 4, 2004

### PhysicsNovice

Please review the correctness of these basics physics questions. Add any comments or helpful hints to help my rudimentary understanding. I am truly a "physics novice." Thanks.

Physics Problems – Round 2

1. An object moves with a constant speed of 20 meters per second on a circular track of radius 100 m. What is the acceleration of the object?

a. zero
b. 0.4 m/s/s
c. 2 m/s/s
d. 4 m/s/s*

2. What force is needed to make an object move in a circle?

a. kinetic friction
b. static friction
c. centripetal force*
d. weight

3. A car goes around a curve of radius r at a constant speed. What is the direction of the net force on the car?

a. toward the curve's center*
b. away the curve's center
c. toward the front of the car
d. toward the back of the car

4. If a car goes around a curve at half the speed, the centripetal force on the car is:

a. four times as big
b. half as big
c. one-fourth as big*

5. According to Newton, the greater the distance between masses of interacting objects, the:

a. less the gravitational force between them
b. more the gravitational force between them
c. less the force by the square of the separation distance*
d. none of these

6. If the radius of earth somehow decreased with no change in mass, your weight would:

a. increase*
b. not change
c. decrease
7. The force of gravity acting on you will increase if you:

a. burrow deep inside the planet
b. stand on a planet with a radius that is shrinking
c. both of these*
d. none of these

8. A hollow spherical planet is inhabited by people who live inside it, where the gravitational field is zero. When a very massive ship lands on the planet’s surface, inhabitants find that the gravitational field inside the planet is:

a. still zero
b. non-zero, directed toward the spaceship*
c. non-zero, directed away from the spaceship

9. A very massive object A and a less massive object B move toward each other under the influence of mutual gravitation. Which force, if either, is greater?

a. The force on A
b. The force on B
c. Both forces are the same*

10. A woman who normally weights 400 N stands on top of a very tall ladder so she is one earth radius above the Earth’s surface. How much does she weigh there?

a. zero
b. 100 N*
c. 200 N
d. 400 N
e. none of these

2. Oct 4, 2004