This set of Class 11 Physics Chapter 5 Multiple Choice Questions & Answers (MCQs) focuses on “Newton’s Second Law of Motion”.
1. What is the force applied on a body with 5 kg of mass and an acceleration of 7 m/s2?
a) 35 N
b) 5 N
c) 7 N
d) 0 N
View Answer
Explanation: According to the second law of motion, the force on a body is equal to the rate change of its momentum. On simplifying we get, F = ma. Therefore, Force = 5 x 7 = 35 N.
2. Unit of force is _____
a) Newton
b) Pascal
c) Byte
d) Gram
View Answer
Explanation: The unit of force is newton. This unit has been given after the name of the famous scientist Sir Isaac Newton who had given the three laws of motion. The force on anybody can be found with the help of the second law of motion.
3. The unit ‘Newton’ is equivalent to ______
a) Kg-m/s2
b) Kg-m/s
c) Kg/m/s2
d) Kg2-m/s2
View Answer
Explanation: From the second law of motion we get that F = ma, when the mass is not changing. Putting in the units, we get, Newton = Kg-m/s2.
4. If the force acting on a body is 10 N, and the acceleration is 4 m/s2, what can be the mass of the body?
a) 2.5 Kg
b) 25 Kg
c) 0.25 Kg
d) 5 Kg
View Answer
Explanation: From the second law of motion we get that F = ma, when the mass is not changing. Putting in the values, we get, Force = 10 = m x 4. Which will result in m = 2.5 Kg.
5. If the force acting on a body is 50 N, and the mass is 5 kg, what can be the acceleration of the body?
a) 10 m/s2
b) 80 m/s2
c) 8 m/s2
d) 0.8 m/s2
View Answer
Explanation: From the second law of motion we get that F = ma, when the mass is not changing. Putting in the values, we get, Force = 10 = 5 x a. Which will result in a = 10 m/s2.
6. An example of variable mass system is _____
a) A car moving
b) A rocket taking off
c) A bicycle moving
d) A man walking
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Explanation: In case of a rocket taking off, the mass of the fuel is large and cannot be neglected. As the rocket starts moving, a large amount of fuel is getting burnt out from the nozzle, hence the total mass decreases. Hence it is a variable mass system.
7. How do we calculate force in a variable mass constant velocity system?
a) F = ma
b) F = mv
c) F = v(dm/dt)
d) F = m/t
View Answer
Explanation: The general expression for force is F = dp/dt. On solving we get, F = m(dv/dt) + v(dm/dt). Since the system is constant velocity, hence dv/dt = 0. What remains is F = v(dm/dt).
Sanfoundry Global Education & Learning Series – Physics – Class 11.
To practice all chapters and topics of class 11 Physics, here is complete set of 1000+ Multiple Choice Questions and Answers.
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- Check Class 11 - Physics Books
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