Which one of these are non-contact forces

friction

gravity

normal force

pushing force

A wave has a wavelength of 10 mm and a frequency of 5 hertz. what is its speed?

What are polarized waves

The amount of the mass object has per its volume is knows as

Where could convection current form check all that apply

During a particular thunderstorm, the electric potential between a cloud and the ground is vcloud - vground = 1.5 x 108 v, with the cloud being at the higher potential.

Which of the following would change a boat's center of gravity? A. Change the material it is made from B. Put a small cabin directly over the current center of gravity C.

A boat leaves a dock at 7:00 pm and travels due south at a speed of 20 km/h. another boat has been heading due east at 15 km/h and reaches the same dock at 8:00 pm.

Two students are playing hockey with 0.4-N wad of paper. One student hits the wad and it slides across his desk, slowing down at a rate of 0.6 m/s/s. Find the coefficient of kinetic friction between the wad and the desk?

A uniform solid sphere rolls down an incline. (a) What must be the incline angle if the linear acceleration of the center of the sphere is to have a magnitude of 0.

Which one of these are non-contact forces friction gravity normal force pushing force