You want to pull a 7 kg block up a frictionless ramp with an acceleration of 3.8 m/s2.

Question

You want to pull a 7 kg block up a frictionless ramp with an acceleration of 3.8 m/s². What force do you need to apply on the block along the direction of the ramp's surface if the ramp is angled at 30 degrees above the horizontal?

Answer 1

along the ramp, gravity pulls block with mg *sin(30)=35 N

To accelerate the block, the net force along the ramp should be ma=7*3.8=29.6N

The acceleration has two possible direction, up and down.

If going down, the force to pull will be 35-29.6=5.4N

if going up, the force to pull will be 35+29.6=64.6 N