In this blog you will find the correct answer of the Coursera quiz How Things Work: An Introduction to Physics week 2 mixsaver always try to brings best blogs and best coupon codes
 

Week- 2

Skating

 

1. While searching for your keys, you place your cup of coffee on the roof of your parked car. Unfortunately, you forget about the coffee and climb into the car without it. As you start driving the car forward, you hear the coffee hit the ground behind the car. Why didn’t the coffee stay on the roof of the car?

 

  • The coffee’s inertia kept it essentially motionless as the car accelerated forward and left the coffee behind.
  • The car’s roof pushed the coffee backward, in the direction opposite the car’s velocity.
  • The car’s roof pushed the coffee backward, in the direction opposite the car’s acceleration.
  • The coffee pushed itself backward as the car pushed itself forward.

2. An African swallow is flying east at 60 mph (about 100 km/h) and a European swallow is flying west at 60 mph (about 100 km/h). These two swallows have _______________.

 

  • the same speed and the same velocity.
  • different speeds and different velocities.
  • the same speed, but different velocities.
  • different speeds, but the same velocity.

3. You kick a soccer ball (a football) toward the goal. When the fast-moving ball is midway to the goal and nothing is touching it, why is the ball moving toward the goal? [Ignore any effects due to the air or gravity.]

 

  • The force of your kick continues to push the ball forward steadily as the ball moves from you to the goal.
  • Inertia keeps the ball in motion.
  • The force of your kick continues to push the ball forward, although that force decreases gradually as the ball moves from you to the goal.
  • The ball exerts a forward force on itself even after the ball leaves your foot.

4. Which of the following is experiencing zero net force?

 

  • The driver of a car that is increasing its forward speed at the start of a race.
  • A passenger in an elevator that is slowing down after its trip from the ground floor to the 10th floor.
  • A child who is riding a carousel (a merry-go-round) and is traveling around in a circle at a steady pace.
  • A water-skier who is being pulled forward by a speedboat and is moving in a straight-line path at a steady speed.

5. You are riding your bicycle forward on a level road, traveling in a straight line at a steady pace. An animal suddenly runs in front of you, so you apply the brakes quickly and stop just in time to avoid hitting the animal. While the brakes are on and you are experiencing a large net force, what is the direction of velocity and acceleration, respectively?

 

  • Your velocity is backward and your acceleration is backward.
  • Your velocity is backward, but your acceleration is forward.
  • Your velocity is forward, but your acceleration is backward.
  • Your velocity is forward, but your acceleration is zero.

6. You are coasting forward at constant velocity on your inline skates. Suddenly, another skater pushes you so that the net force you are experiencing points toward your left. While your net force points toward the left, your acceleration _______________.

 

  • is zero.
  • points at an angle between forward and toward your left.
  • points forward (in the direction of your velocity).
  • points toward the left (in the direction of your net force).

7. Two skaters are coasting forward across the ice. The skater in red has a greater mass than the skater in blue. You begin pushing the two skaters forward with equal forces. How do they move while you are pushing them? [The correct answer must always be true, no matter how fast the skaters were moving before you began pushing them.]

 

  • The skater in red experiences less acceleration than the skater in blue.
  • The skater in red experiences more acceleration than the skater in blue.
  • The skater in red moves faster than the skater in blue.
  • The skater in red moves slower than the skater in blue.

8. In what circumstance can you be accelerating forward and still be moving at a constant velocity?

 

  • When you are moving backward and therefore slowing to a stop.
  • When you are moving toward the side and your path is therefore curving.
  • When you are experiencing zero net force.
  • In no circumstance. If you are accelerating, you velocity is changing with time.

9. You are dragging a heavy chair across the floor and that chair is moving toward the east at constant velocity. The net force on the chair __________________.

 

  • is zero.
  • points toward the east.
  • points downward and eastward (at an angle between the two individual directions).
  • points upward and eastward (at an angle between the two individual directions).

10. A set of dishes sits motionless on a slippery silk tablecloth. If you pull the tablecloth sideways quickly, it will slide out from under the dishes and leave the dishes almost unaffected. Why won’t that same result occur if you pull the tablecloth sideways slowly?

 

  • Inertia lasts only for a short time, so objects at rest stay at rest only for a short time.
  • The moving tablecloth exerts small forces on the dishes and, given enough time, those forces will overwhelm inertia and cause the dishes to move with the tablecloth.
  • The tablecloth is slippery only at high speeds. At low speeds, it clings to the dishes like glue.
  • The tablecloth can hold the dishes in place only when the tablecloth is moving at high speeds.

 

 

 

 

Important Links:

Trustpilot