Newton’s Laws 10min test q1 Motion direction pull Weight (force due to gravity – don’t just say ‘gravity’) Friction (opposite to the motion) Contact force Show forces as pulls, not pushes in these diagrams, and show object as a point or a box

1c If the object is accelerating, either getting faster or slower, then one forces must be bigger than the force opposite to it.

q2 Newton’s first law: if there is no resultant force acting on an object then it will not change its velocity (that means it will stay at rest or, if already moving, will continue in a straight line at a steady speed)

q3 Newton’s second law: If there is a resultant force acting on an object then it will change its velocity That means it will either get faster or slower or it will change its direction of motion. This law gives us an equation: F=ma where F is the resultant force and ‘a’ is the acceleration that the mass m has

q4 Pull = 20N, Friction = 6N So resultant force = 20-6 = 14N Mass = 7kg F=ma gives us 14 = 7a so acceleration a = 2m/s 2

q5 Mass is the amount of substance in a body Weight is the force of the earth’s gravity pulling the mass downwards b) Using F=ma we have Weight = mass x 10 because gravity always accelerates mass at 10m/s 2 on the earth (called g). But mass has to be in kg So 300g (0.3kg) has a weight of 3N