A tennis ball launcher works by using a spring to propel the ball forward.
One model of tennis ball launcher has
advertised that it is capable of imparting
15,000 J of kinetic energy to a 0.5 kg ball
initially at rest. A student carefully measures the
compression of the spring to be 0.10 m.
What is the value of the spring constant for the
tennis ball launcher according to the data
provided?

The membrane surrounding a living cell consists of an inner and an outer wall that are separated by a small space. assume that the membrane acts like a parallel plate capacitor in which the effective charge density on the inner and outer walls has a magnitude of 7.0 × 10-6 c/m2. (a) what is the magnitude of the electric field within the cell membrane? (b) find the magnitude of the electric force that would be exerted on a potassium ion (k+; charge = +e) placed inside the membrane.

Polly is pushing a box across the floor with a force of 30 n. the force of gravity is –8 n, and the normal force is 8 n. which value could describe the force of friction if polly could not move the box?

What is the measurement of how fast an object moves relative to a reference point?