work is being done when a force:
a) is exerted while pulling a wagon up a hill
b) acts vertically on a cart that can only move horizontally
c) is exerted by one team in a tug-of-war when there is no movement
d) of gravitational attraction acts on a person standing on the surface of the Earth
TELL ME
c) is exerted while pulling a wagon up a hill
explanation: If object is not displaced, no work is done. An applied force has to result in the movement of some object over a distance.
a) Definitely! Especially if the wagon is filled with snacks - that's some serious work!
b) Well, unless the cart starts levitating or something, I'd say not much work is being done vertically on a horizontally moving cart. Gravity might be a bit confused though.
c) Ah, the good ol' tug-of-war! If those two teams are just tugging with all their might but not budging an inch, it's safe to say they're not really getting any work done. Just a lot of huffing and puffing.
d) Gravity, my friend! Standing on the Earth's surface, you might not feel like you're working. But trust me, gravity is always pulling its weight!
To determine when work is being done, you need to understand what work means in the context of physics. Work is defined as the transfer of energy that occurs when a force is applied over a certain distance. Mathematically, work is calculated by multiplying the magnitude of the force applied by the distance over which the force is exerted and the cosine of the angle between the force and the direction of motion.
Now, let's apply this definition to each scenario:
a) When a force is exerted while pulling a wagon up a hill:
In this case, work is being done because the force (pulling the wagon) is applied over a distance (the distance traveled while pulling the wagon up the hill). As long as the force and the displacement have non-zero magnitudes and are not perpendicular, work is being done.
b) When a force acts vertically on a cart that can only move horizontally:
In this scenario, no work is being done because the force is acting vertically, while the cart only moves horizontally. Since the force and the displacement are perpendicular to each other, the angle between them is 90 degrees, and the cosine of 90 degrees is zero. Therefore, no work is being done.
c) When one team exerts a force in a tug-of-war with no movement:
In this case, no work is being done because although a force is being exerted, there is no displacement. Work is defined as force multiplied by displacement, and if the displacement is zero, then the work done will also be zero.
d) When the gravitational attraction acts on a person standing on the surface of the Earth:
In this scenario, no work is being done because the person is not moving vertically. Even though there is a force of gravitational attraction acting on the person, no displacement is occurring, and therefore no work is done.
By analyzing the scenarios using the definition of work and considering the relationship between force, displacement, and angle, we can determine when work is being done.