Download presentation

Presentation is loading. Please wait.

Published byRachelle Akin Modified over 2 years ago

1
7-2 Projectile Motion

2
Independence of Motion in 2-D Projectile is an object that has been given an intial thrust (ignore air resistance) Football, Bullet, Baseball Moves through the air under the force of gravity Path is called Trajectory If you know the force of the thrust, you can determine trajectory

3
Independence of Motion in 2-D If you hit a golf ball, throw a football, only force acting on the projectile is gravity (long range) Gravity acts same in vertical direction Horizontal force has no effect on vertical component

4
Combination of vertical drop and horizontal moment give object a parabola trajectory

5
Strategy Separate into vertical and horizontal motion problem Vertical motion is treated like a straight up or down movement (g) Horizontal motion treated like a constant velocity problem No thrust and air drag neglected No horizontal forces acting (a = 0) Motions are connected by time variable Solve for time in one of the dimensions and will give you other

6
Equations Y-direction: v y = -gt y = y 0 – (1/2)gt 2 t = √ -2(y – y 0 ) g X-Direction x = x 0 + v x0 t

7
Stone is thrown horizontally at 15 m/s from top a cliff 44 meters high A) How far from the base of the cliff does the stone hit the ground? Known X 0 = 0v x0 = 15 m/s y 0 = 0v y0 = 0a = -g Unknown X when y = -44 m V at that time a F g = F net

8
How far from the base of the cliff does the stone hit the ground? Y-direction y = y0 – (1/2)gt2 t = √ -2(y-y0)so: = √ -2(y) / g g √ -2(-44 ) / -9.8 m/s2 = 3.0 sec

9
How far from the base of the cliff does the stone hit the ground? X direction x = x 0 + v x0 t x = (15 m/s)(3.0 m/s) = 45 meters from the base

10
How fast is it moving the instant before it hits the ground? V y = -gtv x = -(9.80 m/s2)(3.0 s) = -29 m/s v y v v =√ v x 2 + v y 2 = √(15 m/s) 2 + (-29 m/s) 2 = 33 m/s

11
Projectiles Launched at an Angle Initial velocity has an initial horizontal and vertical component Rises with slowing speed and falls with gaining speed Max Height height of projectile when vertical velocity is zero and only has horizontal component y = y i + V yi t – (1/2)gt 2 Range (R) Horizontal distance the projectile travels

12
Problem A ball is launched with an initial velocity of 4.47 m/s at an angle of 66 o above the horizontal. A) What is the max height the object attained? B) How long did it take the ball to return to the launching height? C) What was the range? Known x i = 0y i = 0 v i = 4.47 m/sθ = 66 o a = -g Unknown y when Vy = 0t = ??x when y = 0

13
Equations Needed Y direction: V yi = vi sinθ(4.47)sin 66 o V yi = 4.08 m/s *** V y = V yi – gt *** y = y i + V yi t – (1/2)gt 2 x direction V xi = v i cos θ V x = V xi x = x i + v xi t

14
What is the max height the object attained? V y = 0, t = v yi / g t = (4.08 m/s) / (9.80 m/s 2 ) t = 0.420 s y max = v yi t – (1/2)gt 2 = (4.08 m/s)(0.420) – (1/2)(9.80)(0.420) 2 y max = 0.850 m

15
How long did it take the ball to return to the launching height? y = 0 y = y i + V yi t – (1/2)gt 2 0 = 0 + V yi t – (1/2)gt 2 t = 2v yi / g = 2(4.08 m/s) / (9.80) t = 0.83

16
What was the range? x = R R = V xi t = (4.47 m/s)(cos 66 o )(0.83 s) R = 1.5 m

Similar presentations

OK

Projectile Motion Projectile motion: a combination of horizontal motion with constant horizontal velocity and vertical motion with a constant downward.

Projectile Motion Projectile motion: a combination of horizontal motion with constant horizontal velocity and vertical motion with a constant downward.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on team management skills Ppt on nuclear family and joint family photos Ppt on cd rom drive Ppt on time management for nurses Ppt on power sharing in democracy who makes Ppt on online education in india Download ppt on gender sensitivity Ppt on two point perspective grid Ppt online download for youtube Ppt on perimeter and area of plane figures