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Question 1:

A block of mass 5 kg is at rest on a horizontal surface. What is the net force acting on the block?

A) 0 N
B) 5 N
C) 9.8 N
D) 50 N

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Explanation: The correct answer is A) 0 N. According to Newton's first law of motion, an object at rest will remain at rest if the net force acting on it is zero. In this case, since the block is at rest, the net force acting on it must be zero.

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Question 2:

A force of 20 N is applied to an object of mass 4 kg. What is the acceleration of the object?

A) 5 m/s^2
B) 8 m/s^2
C) 16 m/s^2
D) 80 m/s^2

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Explanation: The correct answer is A) 5 m/s^2. According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Applying Newton's second law, we can calculate the acceleration using the formula a = F/m. Therefore, the acceleration is 20 N / 4 kg = 5 m/s^2.

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Question 3:

A car of mass 1000 kg experiences a net force of 2000 N. What is the acceleration of the car?

A) 0.5 m/s^2
B) 2 m/s^2
C) 20 m/s^2
D) 200 m/s^2

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Explanation: The correct answer is B) 2 m/s^2. Using Newton's second law of motion, we can calculate the acceleration using the formula a = F/m. In this case, the net force is 2000 N, and the mass is 1000 kg. Therefore, the acceleration is 2000 N / 1000 kg = 2 m/s^2.

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Question 4:

A 10 kg mass is suspended by two strings, as shown in the diagram. What is the tension in each string?

A) 10 N in each string
B) 20 N in each string
C) 10 N in one string and 20 N in the other string
D) It depends on the length of the strings

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Explanation: The correct answer is A) 10 N in each string. According to Newton's third law of motion, the tension in each string is equal and opposite to the weight of the suspended mass. Since the mass is 10 kg and the acceleration due to gravity is approximately 9.8 m/s^2, the weight of the mass is 10 kg * 9.8 m/s^2 = 98 N. Therefore, the tension in each string is 98 N / 2 = 49 N. So, the correct answer is 10 N in each string.

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Question 5:

A person pushes a 20 kg box with a force of 100 N. If the frictional force between the box and the surface is 50 N, what is the acceleration of the box?

A) 5 m/s^2
B) 2 m/s^2
C) 1 m/s^2
D) 0.5 m/s^2

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Explanation: The correct answer is D) 0.5 m/s^2. To calculate the acceleration of the box, we need to subtract the frictional force from the applied force and divide the result by the mass of the box. The net force acting on the box is 100 N - 50 N = 50 N. Therefore, the acceleration is 50 N / 20 kg = 2.5 m/s^2. However, since the frictional force opposes the motion, the acceleration of the box will be in the opposite direction. Hence, the acceleration of the box is -2.5 m/s^2 or -0.5 m/s^2.