Work Puzzles
Test your understanding of work, its definition, formula, units, and practical examples with these interactive puzzles!
Puzzle 1: Define work in physics.
Hint: Work involves force and displacement.
Answer: Work is defined as the product of force and the displacement of an object in the direction of the force.
Puzzle 2: Write the formula for work done.
Hint: It involves force, displacement, and the angle between them.
Answer: The formula for work done is W = Fd\cos\theta, where F is the force, d is the displacement, and \theta is the angle between the force and displacement.
Puzzle 3: What is the SI unit of work?
Hint: It's named after a famous scientist.
Answer: The SI unit of work is the joule (J).
Puzzle 4: State the conditions under which work is done.
Hint: Think about force and displacement.
Answer: Work is done when a force is applied, and the object moves in the direction of the force or has a component of displacement in the force's direction.
Puzzle 5: How much work is done if a force acts perpendicular to displacement?
Hint: Consider the angle in the work formula.
Answer: No work is done because the angle between force and displacement is 90^\circ, and \cos 90^\circ = 0.
Puzzle 6: Does a coolie carrying a load while walking on a horizontal path do work against gravity?
Hint: Think about the direction of force and displacement.
Answer: No work is done against gravity because the force due to gravity is vertical, and displacement is horizontal. Hence, the angle is 90^\circ, and \cos 90^\circ = 0.
Puzzle 7: Does the moon do work while revolving around the Earth?
Hint: Think about the direction of gravitational force and the moon's displacement.
Answer: The moon does no work while revolving around the Earth because the gravitational force acts perpendicular to its displacement at all points in the orbit.
Puzzle 8: Is work a scalar or vector quantity?
Hint: Work has magnitude but no direction.
Answer: Work is a scalar quantity because it has only magnitude and no specific direction.
Puzzle 9: A person applies a 50 N force to push a box 5 m on a flat surface. How much work is done?
Hint: Use the work formula W = Fd \cos \theta and assume \theta = 0^\circ.
Answer: W = Fd\cos 0^\circ = 50 \times 5 \times 1 = 250 \, \text{J}.
Puzzle 10: When is the work done by gravity negative?
Hint: Think about the direction of displacement relative to gravitational force.
Answer: Work done by gravity is negative when an object is moved upward, against the force of gravity.