1. Chapter 7 Projectile Motion

2. The motion of an object that has been thrust into air where the only forces acting on it are gravity & air resistance.

3. Projectile Motion Because we ignore air resistance, the only force acting on thrown objects is gravity.

4. Projectile The object that has been given an initial thrust, fired, or thrown into air.

5. Trajectory The path of a projectile as it travels through space.

6. In Projectile Motion The vertical & horizontal components act independently & can be solved independently

7. In Projectile Motion The only force acting vertically is the force of gravity causing downward acceleration.

8. In Projectile Motion There are no net forces acting horizontally; thus, the horizontal velocity is constant.

9. In Projectile Motion Use your velocity formulas to solve for vertical & horizontal motion independently.

10. In Projectile Motion Solve for time in air 1 st Always use the vertical component to solve for the time in air.

11. In Projectile Motion After solving for the time in air, solve for the range or horizontal distanced traveled

12. A rock has been thrown horizontally at 4.0 m/s from a tower 49 m high. Calculate: t air, d H, and v H & v V the instant before impact:

13. A bullet exits a 0.50 m barrel horizontally at 1000.0 m/s from a height of 2.0 m. Calculate: a bullet in barrel, t in barrel, t air,v V at impact, d H :

14. A plane flying horizontally at 250 m/s at an altitude of 4.9 km high drops a bomb. Calculate: t air, d H, and v V the instant before impact:

15. A ball rolls at 75 cm/s off the edge of a 49 cm table. Calculate: t air, d H, and v V the instant before impact:

16. A car traveling at 1500 cm/s goes off the edge of a 0.49 km high cliff. Calculate: t air, d H, and maximum v V :

17. A car accelerates at 5.0 m/s 2 for 250 m before going off the edge of a 0.49 km high cliff. Calculate: t & max v on the ground, & t, d H, and max v V in air:

18. A cannon ball is fired at 1000.0 m/s at 53 o from horizontally. Calculate: max height, t air,v V at impact, d H :

19. Repeat the last problem with a cannon ball exiting the barrel at the same speed with angles of 40 o, 45 o, & 50 o

20. Assumming all factors are the same for that cannon, Calculate its maximum range:

21. A ball is thrown at 25 m/s at 45 o from horizontal. Calculate: t air, maximum height, v V at impact, d H :

22. A 25 Mg car is accelerated from rest at 5.0 m/s 2 up a 250 m ramp at 37 o from horizontal. Calculate: t, & v f on the ramp, and d V, d H, t, and maximum v V in air:

23. A 1.0 Mg block slides from rest down a 250 m ramp (  = 0.20) at 37 o from horizontal that ends 490 m above the ground. Calculate: t, & v f on the ramp, and d H, t, and maximum v V in air:

24. Review

25. A sled coasts off a 0.49 km cliff at 18 km /hr. Calculate: t air, max v V, & d H :

26. A catapult launches a 250 kg rock at 100.0 m/s at 37 o from horizontal. Calculate: t up, d V, t air, & d H :

27. Define each of the following DistanceDisplacement SpeedForce Velocity Acceleration

28. Give Units for each of the following DistanceDisplacement Speed Acceleration VelocityForce

29. v f = v i + at d = v i t + ½ at 2 v f 2 = v i 2 + 2ad

30. Projectile Motion Projectile Trajectory

31. A 25 Mg sled slides from rest down a 500.0 m slope (  = 0.10) at 37 o from horizontal that ends 2.45 km above the ground. Calculate: t, & v f on the slope, and d H, t air, and the maximum v V in air:

32. A 250 Mg sled accelerates at 3.0 m/s 2 up a 250 m ramp (  = 0.25) at 53 o from horizontal. Calculate: F a, t ramp, v f ramp, t air, d v, & d H

33. A 0.10 Mg cycle is accelerated with a force of 500.0 N for 10.0 s before hitting a 25 m ramp at 37 o from horizontal. Draw the system and Calculate: v at bottom & top of ramp, and t, d v, & d H in the air

34. An airplane is flying horizontally due west at 360 km/hr at an altitude of 0.49 km & drops a 2000 lb bomb. Draw the system and Calculate: t air, maximum v V, & d H.

35. A 50.0 kg person skis (  = 0.010) down a 3.0 km ski trail with an average slope of 30 o. Draw the system and Calculate: a, t, maximum v on the trail

36. British Ships had cannons with muzzle velocities of 400 m/s while the cannons at Ft McHenry could fire at 500 m/s. The British could elevate to 45 o while the Americans could elevate to 18 o. Which cannons had the greater range.

37. Expanding gases produce about 10,000 N of force in a gun barrel. One nation wants to build a cannon that will deliver a 2,000 kg cannon ball 200 km. Calculate the length that the barrel must be. Because you are estimating round g to –10 m/s 2.

38. A B    = 37 o  = 53 o Y = 1.00 kN X Y C

39. A B   C F H of A F H of B WYWY W x + F V of C F H of C F V of AF V of B + F V of C

40. A B   C F H of B WYWY W x + F V of C F H of C F V of A F V of B F V of C F H of A

41. A 200.0 kg rock is catapulted at 53 o from horizontal at about 0.10 km/s. Draw the system and Calculate: t, d v, & d H in the air

42. A rock is thrown at 37 o from horizontal at about 25 m/s. Draw the system and Calculate: t, d v, & d H in the air