Phy 213 Quiz 4 Forces II 10 pts each Oct 8, 2004

1. A 20 kg mass is pulled along on a horizontal plane by a horizontal force of 50 N. The coefficient of kinetic friction between the plane and the mass is 0.2 . What is the acceleration of the mass?

2. An object slides down a plane whose incline makes an angle of 53° with the horizontal. It's acceleration down the plane is 4 m/s². What is the coefficient of kinetic friction ?

3. A 30 kg object is pulled along a horizontal surface at constant speed by the force indicated. The coefficient of kinetic friction between surfaces is 0.3 . What is the magnitude of the force F ?

4. A student places a glass block on a board and slowly increases the incline of the board until the block just begins to move. If this angle is 53°, what is the coefficient of static friction between glass and the board?

5. Elvira pushes on the box with all her might horizontally. The block acclerates up the hill 2 m/s². If the coefficient of kinetic friction between the box and the hill is µ_k = .4, what is the force F with which Elvira pushes the box?