astronomy

Descriptive Astronomy 201 Quiz 4

Name: ___________________________________ Section: _____________ __________________________________________________________________________________________________________

This quiz contains 2 bonus questions. (Points 10)

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

1) The acceleration of gravity g is ~10 m/S2 at the surface of Earth? A) False B) True

2) On the moon A) Your mass is the same; weight is less B) Your mass is the less; weight is the same C) Both your mass and the weight arethe same D) Your mass is the same; weight is greater

3) If an object's velocity is doubled, its momentum is A) doubled. B) halved. C) dependent on its acceleration. D) unchanged.

Note: Momentum of an object = Mass of the object × Velocity of the object Momentum = m× v

4) You are standing on a scale in an elevator. You feel your weight is less suddenly decreases and remains decreased. What do you conclude?

A) The elevator is accelerating upwards. B) The elevator is moving at a constant velocity downwards. C) The elevator is accelerating downwards. D) The elevator is moving at a constant velocity upwards.

5) How does a rocket launched into space take off? A) By converting mass-energy to potential energy. B) By achieving lift from its wings in the same way that airplanes do. C) Hot gas shoots out from the rocket and, through the conservation of momentum, the rocket moves in the

opposite direction. D) Its rocket engines push against the launch pad, propelling the rocket upwards.

Hint: This is an example of Newton's third law (Action- Reaction Law) of motion.

6) Suppose you drop a feather and a hammer on the Moon from the same height at the same time. What will happen?

A) They will hit the ground at the same time. B) The hammer will hit the ground first. C) They will float in space because of the lack of gravity on the Moon. D) The feather will hit the ground first.

7) If a spinning object suddenly gets bigger in diameter (strech), what happens to its rotation rate? A) It decreases. B) It is unaffected. C) It increases.

Hint: Think about a spin. of an ice skater.

Descriptive Astronomy 201 Spring 2019

8) Newton's second law states: sum of forces (Net force) = mass × acceleration. According to this, what property can you determine if you observe the acceleration of an object with a known mass?

A) the current location of the object B) the sum total of all forces acting on the object C) the current velocity of the object D) the value of a single force acting on the object

9) He realized the laws of gravity applied to objects in space and on the Earth. A) Newton B) Galileo C) Copernicus D) Kepler

This diagram represent the orbital path of Earth around the sun.

10) Which is true about the Earth's orbital angular momentum? A) Earth's orbital angular momentumm is greater when the earth is close to the Sun. B) Earth's orbital angular momentumm is less when the earth is far away from the Sun. C) Its orbital angular momentum does not change.

Aangular momentum = m × v× r

11) The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. According to this equation, if the product of masses of two objects increases, what happens to the gravitational force between them?

A) The force drops instantly to zero. B) The force decreases. C) The gravitational force is not affected by distance. D) The force increases.

12) Newton's version of Kepler's third law states: p2 = 2

G(M1 + M2) × a3

In this equation, what does a represent? A) the universal gravitational constant B) the masses of the two objects C) the orbital period D) the average distance between the two objects

2Descriptive Astronomy 201 Spring 2019