1.
Which equation below represents the mathematical expression of Newton's second law of motion?
Correct Answer
B. F = m x a
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. The equation F = m x a represents this relationship, where F is the force, m is the mass, and a is the acceleration.
2.
Doubling the mass of an object has what effect on acceleration?
Correct Answer
B. Halves accleration
Explanation
When the mass of an object is doubled, it will have the effect of halving the acceleration. This is because according to Newton's second law of motion, the acceleration of an object is inversely proportional to its mass. Therefore, when the mass is doubled, the acceleration will be reduced by half.
3.
Acceleration is....
Correct Answer
D. Always in the direction of the net force
Explanation
Acceleration is always in the direction of the net force because acceleration is directly proportional to the net force acting on an object. When there is a net force acting on an object, it causes the object to accelerate in the same direction as the force. If there is no net force or the forces acting on the object are balanced, then there is no acceleration. Therefore, the correct answer is that acceleration is always in the direction of the net force.
4.
Mass is _________________ proportional to acceleration.
Correct Answer
A. Inversely
Explanation
Mass is inversely proportional to acceleration. This means that as mass increases, acceleration decreases, and vice versa. In other words, if the mass of an object is doubled, its acceleration will be halved. This relationship is described by Newton's second law of motion, which states that the acceleration of an object is directly proportional to the force applied to it and inversely proportional to its mass. Therefore, as mass increases, the force required to accelerate the object also increases.
5.
Force is _________________ proportional to acceleration.
Correct Answer
B. Directly
Explanation
Force is directly proportional to acceleration means that as the force applied to an object increases, the acceleration of the object also increases. This relationship implies that if the force is doubled, the acceleration will also double, and if the force is tripled, the acceleration will triple as well. In other words, there is a direct relationship between the force and acceleration, where an increase in force leads to a corresponding increase in acceleration.
6.
If an object is traveling to the right and slowing down, the direction of the net force is...
Correct Answer
B. To the left
Explanation
If an object is traveling to the right and slowing down, it means that there is a force acting in the opposite direction of its motion. According to Newton's second law of motion, the net force acting on an object is directly proportional to its acceleration. Since the object is slowing down, it has a negative acceleration. To achieve a negative acceleration, the net force must also be in the opposite direction of the object's motion. Therefore, the direction of the net force is to the left.
7.
An arrow is fired straight up into the air. After it leaves the bow the direction of the acceleration is...
Correct Answer
B. Down
Explanation
When an arrow is fired straight up into the air, the direction of the acceleration is down. This is because gravity is constantly acting on the arrow, pulling it downwards. Even though the arrow is moving upwards initially, the force of gravity causes it to slow down and eventually reverse its direction, falling back down to the ground. Therefore, the arrow experiences a downward acceleration throughout its trajectory.
8.
Two vehicles are parked on an incline at the top of a hill. One is a small car, the other a very massive truck. You release the parking brake of each at the same time. All other factors being equal, which vehicle accelerates faster?
Correct Answer
A. The car
Explanation
The car accelerates faster because it has less mass compared to the truck. According to Newton's second law of motion, the acceleration of an object is directly proportional to the force applied to it and inversely proportional to its mass. Since both vehicles experience the same force of gravity pulling them downhill, the car, with its smaller mass, will experience a greater acceleration compared to the truck.
9.
The car and the truck accelerate down the hill and reach a flat level surface at the bottom. Which vehicle will coast farther and take longer to come to rest?
Correct Answer
B. The truck
Explanation
The truck will coast farther and take longer to come to rest compared to the car. This is because the truck has more mass and therefore more inertia, making it harder to slow down and stop. Additionally, the truck may have larger wheels or a higher gear ratio, allowing it to maintain its momentum for a longer distance.
10.
An object weighs 30N on earth. A second object weighs 30N on the moon. Which the greater mass? (Note: due to its size, the moon has less gravity than the earth.)
Correct Answer
A. Object on the moon
Explanation
The object on the moon weighs the same as the object on earth because weight is a measure of the force exerted on an object due to gravity. Although the moon has less gravity than the earth, the weight of an object is determined by the mass of the object and the acceleration due to gravity. Since both objects have a weight of 30N, it means they have the same mass.
11.
Doubling the net force on an object has what effect on acceleration?
Correct Answer
A. Doubles accleration
Explanation
Doubling the net force on an object will result in doubling the acceleration. This is because according to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on it. Therefore, increasing the force applied to an object will cause it to accelerate at a faster rate.
12.
Compared to a 1kg block of solid iron, a 2kg block of solid iron has twice as much
Correct Answer
D. All
Explanation
A 2kg block of solid iron has twice as much inertia, mass, and volume compared to a 1kg block of solid iron. Inertia is the resistance of an object to changes in its motion, and since the 2kg block has more mass, it has more inertia. Mass is the amount of matter in an object, and the 2kg block has twice the mass of the 1kg block. Volume refers to the amount of space an object occupies, and the 2kg block has twice the volume of the 1kg block. Therefore, the correct answer is all.
13.
A 10kg block is pushed across a horizontal surface with a horizontal force of 20N against a friction force of 10N. The acceleration of the block in meters per second per second is
Correct Answer
A. 1
Explanation
The acceleration of the block can be calculated using Newton's second law of motion, which states that the acceleration of an object is equal to the net force acting on it divided by its mass. In this case, the net force is the horizontal force of 20N minus the friction force of 10N, resulting in a net force of 10N. Dividing this net force by the mass of the block (10kg) gives an acceleration of 1 meter per second per second.
14.
A water skier has a mass of 79 kg and accelerates at 1.4 m/s^{2}. What is the net force acting on the skier?
Correct Answer
D. 110.6 N
Explanation
The net force acting on an object can be calculated using the equation F = m * a, where F is the force, m is the mass, and a is the acceleration. In this case, the mass of the water skier is given as 79 kg and the acceleration is given as 1.4 m/s^2. Plugging these values into the equation, we get F = 79 kg * 1.4 m/s^2 = 110.6 N. Therefore, the net force acting on the skier is 110.6 N.
15.
What is the mass of an object if it takes a net force of 32 N to accelerate it at a rate of 0.88 m/s^{2} ?
Correct Answer
D. 36.4 N
16.
A net force of 15 N is applied to a cart with a mass of 2.1 kg. How long will it take the cart to travel 2.8 m, starting from rest?
Correct Answer
B. .86 s
Explanation
Find the acceleration by diving 15N/2.1kg. Then use d = 1/2at2 to find the time.
17.
A car has a mass of 820 kg. It starts from rest and travels 41 m in 3.0 s. What is the net force applied to the car?
Correct Answer
A. 7471 N
Explanation
d=Vi(t) + 1/2at2, Vi=0 so d= 1/2at2 solve for a. F=ma
18.
What is the acceleration of a box weighing 666 N if a force of 777 N is applied to it?
Correct Answer
D. 11.4 m/s/s
Explanation
The acceleration of an object can be calculated using Newton's second law of motion, which states that the acceleration is equal to the net force applied to the object divided by its mass. In this case, the force applied is 777 N and the weight of the box is 666 N, which is equivalent to its mass multiplied by the acceleration due to gravity (9.8 m/s^2). Therefore, the net force is 777 N - 666 N = 111 N. Dividing this by the mass of the box will give us the acceleration, which is 111 N / 9.8 m/s^2 = 11.4 m/s^2.
19.
A 120 N force is applied to a block, causing an acceleration of 22.5 m/s^{2}. What is the mass of the block?
Correct Answer
B. 5.33 kg
Explanation
The mass of an object can be calculated using Newton's second law of motion, which states that force is equal to mass multiplied by acceleration. In this case, the force applied is 120 N and the acceleration is 22.5 m/s^2. Rearranging the formula, we can solve for mass by dividing the force by the acceleration. Therefore, the mass of the block is 120 N divided by 22.5 m/s^2, which equals 5.33 kg.
20.
A student tests the second law of motion by accelerating a block of ice at a rate of 3.5 m/s^{2}. If the ice has a mass of 12.5 kg, what force must the student apply to the ice?
Correct Answer
D. 43.75N
Explanation
The force required to accelerate an object can be calculated using Newton's second law of motion, which states that force is equal to mass multiplied by acceleration (F = m * a). In this case, the mass of the ice is given as 12.5 kg and the acceleration is given as 3.5 m/s^2. By substituting these values into the formula, we can calculate the force required: F = 12.5 kg * 3.5 m/s^2 = 43.75 N. Therefore, the correct answer is 43.75N.
21.
A block pushed with a force of 13.5 N accelerates at 6.5 m/s^{2} to the left. What is the mass of the block?
Correct Answer
B. 2 kg
Explanation
The mass of an object can be calculated using the formula F = ma, where F is the force applied, m is the mass of the object, and a is the acceleration. In this case, the force applied is 13.5 N and the acceleration is 6.5 m/s^2. By rearranging the formula, we can solve for the mass: m = F/a = 13.5 N / 6.5 m/s^2 = 2 kg. Therefore, the mass of the block is 2 kg.