Learning Path
Question & Answer1
Understand Question2
Review Options3
Learn Explanation4
Explore TopicChoose the Best Answer
A
Friction always opposes the motion, reducing the net force down the incline.
B
Friction increases the gravitational force, making the block accelerate faster.
C
Friction has no effect if the block is in motion, so net force remains unchanged.
D
Friction acts in the same direction as gravity to assist the motion.
Understanding the Answer
Let's break down why this is correct
Answer
On an incline the component of gravity that pulls the block down is \(mg\sin\theta\). The frictional force always points opposite the motion, so it acts up the slope. Its magnitude is \(\mu N\) (with \(N=mg\cos\theta\)), so while it opposes the gravitational pull, it is usually smaller than \(mg\sin\theta\) when the block is sliding. For example, a 5‑kg block on a 30° incline has a downhill force of about 24. 5 N, but if the coefficient of kinetic friction is 0.
Detailed Explanation
Gravity pulls the block down the slope. Other options are incorrect because Some think friction helps a block speed up, but friction never adds to gravity; it pulls in the opposite direction; The idea that friction disappears when the block is already moving is false.
Key Concepts
Friction
Forces on Inclined Planes
Acceleration
Topic
Friction
Difficulty
medium level question
Cognitive Level
understand
Practice Similar Questions
Test your understanding with related questions
1
Question 1When an object is sliding down an inclined plane, the force that opposes its motion due to the interaction of the surfaces is known as ___.
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2
Question 2If a block of wood slides down an incline and experiences lower friction than expected, what could be a likely cause for this observation?
mediumPhysics
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3
Question 3When analyzing an object on an inclined plane, which factor most directly affects the frictional force acting on it?
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4
Question 4Which of the following statements about friction forces in a sliding object on an inclined plane are true? Select all that apply.
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5
Question 5In a scenario where a block is sliding down an inclined plane, the component of gravitational force acting parallel to the incline is given by _____, where m is mass, g is the acceleration due to gravity, and α is the angle of incline.
mediumPhysics
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6
Question 6A block is placed on a surface and begins to slide when a force of 270 grams is applied. How would you classify the type of friction acting on the block at this moment?
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