1.
Which of my three laws does the following statement satisfy?
Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.
Correct Answer
B. Newton's first law
Explanation
Recall statement of Newton's first law
2.
Which of Newton's three laws does the following example illustrate? If you have a hockey puck sliding along a table, it will eventually come to a stop.
Correct Answer
A. Newton's first law
Explanation
an unbalanced force friction acts on the hockey stick.
3.
Which law states the need to wear seatbelts?
Correct Answer
C. Newton's first law
Explanation
Newton's first law of motion, also known as the law of inertia, states that an object at rest will stay at rest and an object in motion will stay in motion with the same speed and in the same direction unless acted upon by an external force. This law does not directly state the need to wear seatbelts. Seatbelt laws are typically based on principles of safety and the prevention of injuries during accidents. Therefore, the correct answer does not align with the given question.
4.
What is another name for Newton's first law of motion?
Correct Answer
C. Law of Inertia
Explanation
Newton's first law of motion states that an object at rest will stay at rest, and an object in motion will stay in motion with the same speed and in the same direction, unless acted upon by an external force. This concept is commonly known as the law of inertia. Inertia refers to the tendency of an object to resist changes in its motion. Therefore, the correct answer for another name for Newton's first law of motion is the Law of Inertia.
5.
The blood in your head rushes to your feet when riding on an elevator this is descending and abruptly stops.
Correct Answer
A. Newton's first law
Explanation
Blood rushes from your head to your feet while quickly stopping when riding on a descending elevator. Your blood's inertia (resistance to changes in motion) causes it to continue moving downward while you're stopping, so it rushes from you head to your feet.
6.
Which of Newton's Laws best explains why satellites need very little fuel to stay in orbit?
Correct Answer
C. Newton's first law
Explanation
Newton's first law, also known as the law of inertia, states that an object at rest will stay at rest, and an object in motion will stay in motion with the same speed and direction, unless acted upon by an external force. In the case of satellites in orbit, once they are launched into space and set into motion, there is no significant external force acting upon them to slow them down or change their direction. Therefore, they can continue to orbit the Earth without the need for continuous fuel consumption. This is why Newton's first law best explains why satellites need very little fuel to stay in orbit.
7.
A ball is moving upwards and to the left. A net force that points upwards and to the left must be acting on the ball.
Correct Answer
B. False
Explanation
The net force points in the direction of the acceleration, not necessarily in the direction of the velocity.
If the net force points in the direction of velocity, the object will speed up. If the net force points opposite to the velocity, the object will slow down.
Since we don't know the acceleration of this ball which is moving up and left, we can't say anything for sure about the net force.
8.
When no net force is applied to a moving object, it still comes to rest because of its inertia.
Correct Answer
B. False
Explanation
If an object comes to rest then a net force is acting on it. Otherwise moving object continues to be in motion.
9.
Objects in orbit around the Earth (like a satellite) must have a net force acting on them.
Correct Answer
B. True
Explanation
An object in orbit may have a constant speed, but its direction is constantly changing as it moves in a circle (or ellipse) and, thus, its velocity is also changing (remember, velocity takes into consideration speed and direction). Therefore, there must be a net force acting on it. This is the net force of Earth's gravity acting on the object.
10.
Objects tend to stay moving because of a force called inertia.
Correct Answer
B. False
Explanation
Inertia is not a force. It is the tendency of an object to resist change in velocity. Mass is a measure of an object's inertia.
11.
A less massive object has more inertia than a more massive object?
Correct Answer
A. False
Explanation
More the mass, more the inertia
12.
A stationary object has no forces acting on it.
Correct Answer
B. False
Explanation
weight( Force) acts downwards, Normal reaction (force) acts upwards.
13.
A 7 kg object is accelerating to the right at 2 km/s2. What is the magnitude of the rightward net force acting on it?
Correct Answer
B. 14000 N
Explanation
Acceleration os in Km/s2. Convert into m/s2.
14.
A 500 N rightward net force is accelerating an object to the right at 5 m/s2. What is the mass of the object (in kilograms)?
Correct Answer
A. 100 Kg
Explanation
m= F/a = 100 Kg