OBJECTIVE FINAL REVIEW PART 2

1. What is force? A push or a pull that gives energy to an object 2. What is the unit of force? Newton

3. What is net force? The combination of all forces acting on an object

4. CALCULATE THE NET FORCE AND DIRECTION OF EACH PICTURE = = = 150 Down and right A

= = = 203 Up and left B

= = = 413 Up and right C

1.Motion 2.Mass 3.Velocity 4.Drag 5.Momentum 6.Gravity 7.Weight 8.Force 9.Friction 10.Inertia 11.Speed 12.Acceleration

6. USE THE FORCE TRIANGLE BELOW TO SOLVE THE FOLLOWING PROBLEMS. BE SURE TO SHOW ALL WORK AND UNITS. a. What is the force needed to move a 45 kg ball 25 m/s 2 ? F = _____ M = _____ A = _____ 45 kg x 25 m/s 2 F = M x A 45 kg 25 m/s N

b. How much mass is needed to move a box with 1500 N of force at 5 m/s 2 ? F = _____ M = _____ A = _____ M = F / A 1500 N / 5 m/s N 300 kg 5 m/s 2

c. What is the acceleration of a 2500 N bike that is 450 kg? F = _____ M = _____ A = _____ A = F / M 2500 N / 450 kg 2500 N 450 kg 5.55 m/s 2

7. DEFINE THE FOLLOWING OF NEWTON’S LAWS: a. Newton’s 1 st Law— b. Newton’s 2 nd Law— c. Newton’s 3 rd Law— An object in (motion/rest) stays in (motion/rest) unless acted upon by an unbalanced force An object acted on by an unbalanced force will accelerate in the direction of force * Force= mass x acceleration For every action there is an equal but opposite reaction

STATE WHICH OF NEWTON’S LAWS—1ST, 2ND, OR 3RD APPLIES TO THE FOLLOWING STATEMENTS. ___ 8. A pencil on a table will stay there until someone picks it up. ___ 9. The skier pushes her poles back to move forward. ___ 10. The reason seat belts are worn. ___ 11. It takes more force to move a bowling ball than a baseball. ___ 12. A fireman turns on a hose and is knocked backwards. 1st 3rd 2nd

___ 13. You pull your little sister around the block in a wagon. ___ 14. An astronaut uses a jet pack to go up as gasses are expelled out the bottom. ___ 15. After you start up your motorbike, as you give it more gas it goes faster. ___ 16. A bird flaps his wings down to fly up. ___ 17. It is easier to push an empty cart around Walmart than a full one. 2nd 3rd

18. DEFINE FRICTION— The force that opposes motion between two surfaces that are in contact with each other

19. HOW DOES FRICTION IMPACT THE MOVEMENT OF AN OBJECT? Friction causes a moving object to slow down. Friction applies force in the opposite direction of the existing path of the object The higher the amount of friction, the more friction exists between the two objects.

20. What is a balanced force? 21. What is an unbalanced force? The total of all forces on an object equals zero; object's motion does not change The net force on an object does not equal zero; results in the object changing its motion

22. TWO MEN OF EQUAL STRENGTH HAVE A TUG-OF-WAR. DRAW THE FORCES THAT ARE ACTING ONTO THE PICTURE. Which man will win the tug-of-war? Left or Right Neither--exerting same force

ANOTHER MAN JOINS EACH END OF THE ROPE. DOES THIS AFFECT THE RESULT OF THE TUG-OF-WAR? IF NOT, WHY NOT? No change--still same about of force being exerted

24. ANOTHER MAN JOINS THE TEAM ON THE LEFT. WHICH TEAM WILL WIN THE TUG-OF-WAR NOW? WHY? Team on left--they are using more force

25. IN THE PICTURE FOR QUESTION 24 ABOVE, EACH MAN PULLS WITH A FORCE OF 10 NEWTONS. a. How much force do the team on the left pull with? __________ Newtons b. How much force do the team on the right pull with? __________ Newtons 30 20

26. WHAT IS GRAVITY? The force of attraction between objects that have mass--the size of the pull depends on the masses of the objects.

27. WHAT IS THE DIFFERENCE BETWEEN VELOCITY AND SPEED? Velocity is the speed with a direction, while speed does not have a direction.

28. WHAT IS THE DIFFERENCE BETWEEN VELOCITY AND ACCELERATION? Velocity is a measure of speed at any one instant. Acceleration is a measure of change in speed or direction.

29. WHAT INFORMATION DOES ONE NEED TO CALCULATE VELOCITY? Divide your distance traveled by the time it took to travel that distance and you add your direction to it

30. USE THE FORCE TRIANGLE TO SOLVE THE FOLLOWING PROBLEMS. BE SURE TO SHOW ALL WORK AND UNITS. a. What is the speed of a skater that is going 80 m in 5 s? S = ____ D = ____ T = ____ S = D / T 80 m / 5 s80 m 5 s 16 m / s

b. How long does it take a person jogging 9 km/hr to go 80 km? S = ____ D = ____ T = ____ c. How far does a baby crawl if it goes 2.5 m/s in 7 s? S = ____ D = ____ T = ____ T = D/S 80 km /9 km/hr 9 km/hr 80 km 8.88 hr D = T x S 7 s x 2.5 m/s 7 s 17.5 m 2.5 m/s

31. MATCH THE PART OF THE GRAPH TO THE DESCRIPTION: Quick acceleration: ____ Steady deceleration: ____ Gradual acceleration: ____ Steady speed: ____ C D A B

32. MATCH THE PART OF THE GRAPH TO THE DESCRIPTION: Stationary: ____ Increasing speed: ____ Slow & constant speed: ____ Fast & constant speed: ____ Returning to start: ____ C E A D B