Soren tows a sled with a rope over his shoulder, so the rope slants upward at 30°. Ugo tows an identical sled with an equal force, rope horizontal.
Both sleds cover the same distance. Equal forces, equal distances: do the two ropes do equal work?
Earlier in the course you resolved a force into perpendicular components. Resolve Soren's slanted rope force: a component parallel to the sled's motion, and a component perpendicular to it.
The perpendicular component transfers no energy. You saw why: it has no part parallel to the motion.
That leaves the parallel component to do all the transferring.
Soren's parallel component is smaller than his full force, because part of his force points upward instead of forward.
Ugo's horizontal rope needs no resolving: his whole force is parallel to the motion.
So over the same distance, Soren's slanted rope does less work than Ugo's horizontal one, even though the two forces are equal in size.
The steeper the slant, the smaller the parallel component, and the less work the force does over a given distance.
Talia and Romy each tow identical carts the same distance with equal-size forces. Talia's rope is horizontal; Romy's slants upward at 35°. Who does more work on their cart?
A dock crew drags a boarding ramp with a strap at 45° to its motion. Why does the strap's force do less work over a given distance than an equal force parallel to the motion would?
A dockworker's strap slants upward at 40° while her trunk slides horizontally. An equal force applied horizontally would do more work over the same slide. Explain why.
Only the component of a force parallel to the direction of motion does work on the object.
The slanted strap's parallel component is smaller than its full force, because part of the force points upward.
The horizontal force is entirely parallel to the motion.
So the horizontal force does more work over the same distance.
A kite line slants steeply upward from a kite buggy rolling along a beach. The line's angle to the motion grows from 30° to 70°. What happens to the work the line's force does over each meter, if the force's size stays the same?
The steeper the slant, the smaller the component parallel to the motion.
Only that parallel component does work on the buggy.
The work done over each meter gets smaller.
Romy says: 'When a rope slants upward, only the component of its force parallel to the wagon's motion does work on the wagon.' Is Romy correct?
A rope slanting upward at 25° tows a boat trailer along a ramp lane. Which part of the rope's force does work on the trailer?
Four equal-size forces each act on a crate over equal distances of motion. Which force does the most work on its crate?
A force slants at an angle between 0° and 90° to an object's motion. Which statement is correct?