1. Do Now: A 50 N force at 30 o north of east & a 25 N at 60 o north of east act on a crate. Calculate the net force on the crate. (*hint – NET FORCE is the same thing as the RESULTANT force vector)

2. Ms. Timson’s Physics Review to Conquer 2-D Forces

3. Rules of the Game There will be tribes, as divided by the teacher For each problem which appears on the slide, the tribe will be able to work together to vote on one answer given only the time which will be written on the slide. Tribes cast their answer using their voting cards only in the time allowed. Each team with a correct answer is allowed to cast one vote to remove another tribe from the island. The teacher will have each tribe cast their vote simultaneously by writing the color of the tribe they are voting for on their white board. The teacher will then remove tribes from the island. The teacher will track which tribes are in and which tribes are out of the game with signs on the board. If a tribe is voted out, they can reenter the game by answering the next question correctly to reenter. They will NOT receive a vote for that question but must wait until the next question. Winning tribes will be those still on the island at the end of the game. ***The teacher will be the final judge of any conflicts or confusions – and remember, be respectful and be honest!

4. If angle θ in the figure were decreased, the magnitude of the horizontal force would: a)increase b) decrease c) remain the same 20 seconds θ

5. An 18 N force east & a 10 N force west act on an object simultaneously. The resultant force is: a)8 N east b)b)8 N west c)c)28 N east d)d)28 N west 30 s

6. In the diagram at right the force can be resolved into components that are at a right angle to each other. If the angle θ is less than 45 o, then the vertical component will be ________. A)greater than F B) greater than the horizontal component C) equal to F D) less than the horizontal component 30 seconds θ

7. A box weighing 100 N slides at a constant speed down a plank that is inclined at 33 o to the horizontal. The frictional force acting on the box while it is sliding down the plank must be equal to____ ? A)33 N B) 54 N C) 65 N D) 84 N E) 100 N 1 minute 15 seconds

8. A box weighing 100 N slides at a constant speed down a plank that is inclined at 33 o to the horizontal. What is the coefficient of friction between the box and the plank? A)0.33 B) 0.54 C) 0.65 D) 0.84 E) 1.55 45 seconds

9. A 10.0 kg sled is pulled along level ground with a force of 100.0 N on the rope. The rope makes an angle of 30.0 o with the ground. Assuming that friction is negligible, what is the horizontal acceleration of the sled? A)5.00 m/s 2 B) 8.66 m/s 2 C) 11.55 m/s 2 D) 500 m/s 2 E) 866 m/s 2 1 minute

10. A 5.0 kg box accelerates at 2.0 m/s 2 as it slides down a 30 o incline. How large is the frictional force that acts on the box? a.14.5 N b.24.5 N c.10 N d.42.4 N 30 seconds

11. A 5.0 kg box accelerates at 2.0 m/s 2 as it slides down a 30 o incline. How long does it take the box to slide 8.0 m if it starts from rest? a.16 s b.160 s c.4 s d.8 s 50 seconds

12. A 490 N crate slides at constant speed down a ramp at 50 o from horizontal. Calculate the perpendicular (normal) force exerted by the crate. a.375.4 N b.314.9 N c.490 N d.-490 N 10 seconds

13. A 490 N crate slides at constant speed down a ramp at 50 o from horizontal. Calculate the force which tends to pull the crate down the ramp. 15 seconds

14. A 490 N crate slides at constant speed down a ramp at 50 o from horizontal. Calculate the frictional force between the crate & the ramp. 2 minutes

15. A 490 N crate slides at constant speed down a ramp at 50 o from horizontal. Calculate the frictional coefficient. 1 minute

16. If a force is resolved into x & y components, the magnitude of each component is: a)greater than that of the original force b)equal to that of the original force c)less than that of the original force d)one half of that of the original force 20 seconds

17. The vertical component of the force on the box is given by: a)F A b)F A tan θ c)F A cosθ d)F A sinθ 20 seconds θ

18. For an object on an inclined plane, the normal force becomes ______ as the incline becomes steeper. A) greater B) Less 40 seconds

19. Congratulations! Good luck tomorrow! I know you can conquer your test

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