Understanding Friction: Static and Kinetic

What is the force that prevents a heavy sofa from moving when you push it with all your might?

• Gravitational force

• Kinetic friction

• Normal force

• Static friction

Which type of friction occurs when two surfaces are sliding past each other?

• Kinetic friction

• Static friction

• Fluid friction

• Rolling friction

Why is it generally easier to keep an object moving than to start moving it from rest?

• Because the gravitational force is reduced

• Because the normal force is reduced

• Because static friction is greater than kinetic friction

• Because kinetic friction is greater than static friction

In the given example, what is the normal force acting on a 2 kg object on a surface?

• 39.2 newtons

• 4.9 newtons

• 19.6 newtons

• 9.8 newtons

How do you calculate the force of kinetic friction for an object in motion?

• Multiply the mass by the acceleration

• Multiply the normal force by the coefficient of static friction

• Multiply the normal force by the coefficient of kinetic friction

• Divide the normal force by the coefficient of kinetic friction