1.
Newton's second law of motion states that when a net force acts on an object the object will __________ in the direction of the force.
Correct Answer
C. Accelerate
Explanation
Newton's second law of motion states that when a net force acts on an object, the object will accelerate in the direction of the force. This means that the object will experience a change in its velocity, either by speeding up or slowing down, depending on the direction of the force. Therefore, the correct answer is "accelerate."
2.
What is the formula for Newton's second law of motion?
Correct Answer
A. F=ma
Explanation
Newton's second law of motion states that the force acting on an object is equal to the mass of the object multiplied by its acceleration. This formula, F=ma, represents the relationship between force, mass, and acceleration. It shows that the force experienced by an object is directly proportional to its mass and the rate at which its velocity changes. By using this formula, one can calculate the force required to accelerate an object of a given mass.
3.
How much force is needed to accelerate a 200 kg motorcycle at 4 m/s2?
Correct Answer
B. 800 N
Explanation
To calculate the force needed to accelerate an object, we can use the formula F = m * a, where F is the force, m is the mass, and a is the acceleration. In this case, the mass of the motorcycle is given as 200 kg, and the acceleration is given as 4 m/s^2. Plugging these values into the formula, we get F = 200 kg * 4 m/s^2 = 800 N. Therefore, the correct answer is 800 N.
4.
If a 70 kg skydiver jumped out of a plane, what would be the force of his falling?
Correct Answer
D. 686 N
Explanation
The force of the skydiver's falling would be 686 N. This is because the force of gravity acting on an object is equal to its mass multiplied by the acceleration due to gravity. In this case, the skydiver's mass is 70 kg, and the acceleration due to gravity is approximately 9.8 m/s^2. Therefore, the force of the skydiver's falling would be 70 kg * 9.8 m/s^2 = 686 N.
5.
Gravity near Earth’s surface causes falling objects to accelerate at a rate of 9.8 m/s^{2}.
Correct Answer
A. True
Explanation
The statement is true because gravity on Earth does indeed cause falling objects to accelerate at a rate of 9.8 m/s^2. This acceleration is commonly referred to as the acceleration due to gravity and is the same for all objects regardless of their mass. It means that for every second an object falls, its velocity increases by 9.8 meters per second. This constant acceleration is a fundamental concept in physics and is an important factor in understanding the motion of objects in free fall.
6.
Terminal Velocity is the point at which a free-falling object cannot accelerate any more due to what two are forces working against each other?
Correct Answer
A. Gravity and Air Resistance
Explanation
Terminal velocity is the maximum velocity that a free-falling object can reach when the forces of gravity and air resistance are balanced. Gravity is the force that pulls the object downward, while air resistance is the force that opposes the motion of the object through the air. As the object falls, the force of gravity increases, causing the object to accelerate. However, as the object accelerates, the force of air resistance also increases. Eventually, the force of air resistance becomes equal to the force of gravity, resulting in a net force of zero and causing the object to reach its maximum velocity, known as terminal velocity.
7.
Newton's second law of motion means that a basketball would require more force to accelerate than a bowling ball.
Correct Answer
B. False
Explanation
Newton's second law of motion states that the force required to accelerate an object is directly proportional to the mass of the object. Therefore, a basketball and a bowling ball would require the same amount of force to accelerate if their masses are the same. Since the question does not specify the masses of the basketball and the bowling ball, we cannot conclude that a basketball would require more force to accelerate than a bowling ball. Hence, the correct answer is False.
8.
If 20 N of force were applied to a 16 kg bowling ball, at what rate would it accelerate?
Correct Answer
A. 1.25 m/s2
Explanation
F = ma. If you know F (20 N) and you know mass (16 kg), then you must solve for a. So, a=F/m or a=20/16, which is 1.25 m/s2.
9.
If a ping pong ball falls off a table and hits the ground with 4 N of force applied to it, what is its mass?
Correct Answer
B. 0.41 kg
Explanation
Since the ball is falling from the table we know the acceleration of gravity is 9.8 m/s2. So, we are solving for m. That means m=F/a or m=4/9.8 = 0.41 kg.
10.
Increasing the mass but keeping the force constant causes the acceleration to decrease.
Correct Answer
A. True
Explanation
When the mass is increased while keeping the force constant, according to Newton's second law of motion (F=ma), the acceleration will decrease. This is because the force needed to move a larger mass is greater, and since the force remains constant, the resulting acceleration will be smaller.