Recent content by crysland

I need to find the x-component of the weight so I need to know the mass.

A shopper pushes a grocery cart 20.0 m at constant speed on level ground, against a 35.0 N frictional force. He pushes in a direction 25.0º below the horizontal. Find the force the shopper exerts, using energy considerations. I got stuck on this because they don't give the mass of the cart.

No, it can't

When theta is 0, it means there's no force in the y direction.

the string is horizontal?

When two strings are used to suspend an object, is it possible for one or both of the angles to be zero (that is, one or both strings are horizontal to the ground) ? Why or why not? Deduce whether either of these scenarios is possible. I say no, it's impossible but i really don't know how to...

Yes. So centripetal force that pulls it toward the center is external?

Ok so what is the net external force acting on the car?

A car going in a circle.

Velocity has both magnitude and direction but speed doesn't have direction

An object stays at rest, or if in motion, stays in motion at a constant velocity unless acted on by a net external force.

Describe a situation in which the net external force is not zero, but its speed remains constant. I don't know if this situation is possible to explain.