i have been driving a lot lately and have seen a lot of kinematics in how the car moves. when i back out of my driveway, i have a negative velocity. i typaically drive 35 mi/hr and that is speed not velocity because i don't drive just one way.
When you saw an oblject you are applying a force to the wood causing the wood to split apart. the teeth cut into the wood the wood pushes back with and equal force in the opposite direstion. Newton's 3rd Law
when you lie on your bed gravity is pulling you down but your bed's force is holding you up. this causes the net force to be zero. you are storing your energy for the morning. you change positions while sleeping.
the force of the spring is caused by the force you put on it by pulling the armbar down. the spring creates tencion and when you let go of the armbar, it swings upwards the armbar is stopped by the cross bar but the ball has no force to make it stop causeing it to continue to move.
when the truck tows, it lifts the car a certain displacement with a force. It does work and power on the car it is towing. Its tired must have a lot of traction to add to the power towing the car. The tow works against (g) accelleration due to gravity in order to lift the car.
Whe hanging up curtains, you have to do work on them. The screws in the walls act as. Normal force against gravity. If your curtans are too heavy and your rod isn't strng enough material, gravity may cause a bend in the middle of the rod because the force of gravity is stronger than the stiffness of the rod. Be sure your rod isn't made ofamber because it can cause electrostatic force it rubbed up against the curtain.
When the olimpians ice skate, the do mny tricks. When they jump, they do work on them with power. When they spin, they use centripital force and accelleration. This causes their skates to move in circles because its center seeking. You can find the period and frequency by finding the revolutions per seccond
The gymnast on the balance beam does work and power to jump on the beam and do cart weels. The rhythmic dancer's ribbons go through centripetal force. The force is center seeking which causes the constant change in direction. When the gymnast jumps to the rings he does work and power too.
