AIMS Review Science Review

Force and Motion What is velocity? Speed and direction What is motion? The change in position of an object over time. If you are driving the same speed and direction as another car… Relative to the car are you moving? No! Relative to the ground are you moving? Yes! Explain! Your reference point can tell you whether you are moving or not.

Newton’s 1st Law What is Newton’s 1st law? An object in motion will stay in motion and an object at rest will stay at rest unless acted upon by an unbalanced force. What is inertia? An object’s resistance to change what it is already doing. If you kick a ball, why does it stop and not go on forever? The unbalanced forces acting on the ball cause it to stop. Friction on the ball acts as the unbalanced force bringing it to a stop.

Describing Motion What is speed? How far something travels in one unit of time. What is our formula to find speed? Distance / Time Sharon rides her bike 44 km in 2 hours. What is her speed? 22 km/hr If Dave drives a car at an average speed of 85 km/hr for 3 hours. How far does he travel? 255 kilometers

Speed, velocity, and acceleration What is the difference between speed and velocity? Velocity is rate of motion and direction, while speed is just rate of motion. Determine whether these are speed, velocity, or neither A cactus wren flies west___________ neither A javelin sails north at 5 m/s______________ velocity A western white-tailed dove flies to a saguaro cactus at 4 m/s speed What is acceleration? When an object’s speed OR direction changes What is a force? A push or pull that can cause motion of an object to change

Newton’s 2nd Law What is Newton’s 2nd law? The acceleration of an object is related to the force acting on it and the object’s mass. What is the formula we use for this law? F=MA What do we measure force in? Newtons If the net force on an object is 0, what do we call that? Balanced What is true about balanced forces? It is still or moving at a constant velocity.

Newton’s 2nd Law cont. The net force acting on a 50 kg crate is 0 N. What is the crate’s acceleration? 0 m/s2 What net force will make a 5 kg bowling ball accelerate by 1.5 m/s2 7.5 N If 7.5 N is applied to a 10 kg ball, what is its acceleration? .75 m/s2

Force Diagrams What is a vector? The arrow showing both direction and magnitude (size). 10 N 20 N What is the net force? 30 N to the right 10 N 25 N 15 N to the right

Force Diagrams cont. Does a force diagram show an object’s motion? No, it shows the forces acting on it. Draw a picture in which a single object experiences a force of 15 N to the left and another force of 45 N to the right. 15 N 45 N What is the net force? 30 N to the right