advertisement

Force and Motion Study Guide Gravity- depends on the mass of an object; objects with a larger mass have a stronger pull of gravity The Earth’s gravity pulls objects towards the ground Friction- when two objects rub together it creates this; it causes objects to slow down (Remember our experiment with friction and the balls- Think about how far the balls traveled on different types of surfaces) *Carpet has more friction than tile *Think of other types of surfaces you could compare with the amount of friction If two objects are acted on by the same amount of force on a flat surface, the one with less mass will travel farther and faster If two objects are let go on an incline with the same amount of force, the one with more mass will travel farther Speed= distance/time *A car travels 90 miles in 3 hours. What is the speed? 90/3 = 30 mph *A car travels 40 mph and is going to be moving for 2 hours, how many miles will the car travel? 40 X 2 = 80 miles *A plane travels for 4 hours at a speed of 642 mph, how many miles will the plane travel? 642/4 = 160.5 (About 160 miles) Velocity is the speed of an object with a given direction (60 mph south) *Look back at your graphs and make sure you understand how to interpret the graphs we did in class; The power point is on the website too Balanced vs. Unbalanced Forces- When unbalanced forces act on an object, the object will move in the direction based on the way stronger force is going What would happen if you threw an eraser up in the air? Why? You exerted a force by throwing it up in the air What unbalanced forces are acting on the ball to cause it to come down? Gravity brings it back down and then you are exerting friction by catching it