To start Which hits the ground first? What assumptions are you making?
A LEVEL PHYSICS Year 1 Projectiles and Gravity C B A A* I can describe why the horizontal and vertical components are independent of each other (grade c) I can calculate the horizontal and vertical components of a projectile journey (grade b) B/C Target A/A* Target EP
Projectile motion If we fire a bullet from a gun and drop a bullet at the same instant which hits the ground first? The motion of a projectile can be split into two unrelated components – vertical and horizontal What are the forces acting on an object in the horizontal and vertical components?
A projectile is an object given an initial velocity and then left to move freely under gravity. Projectiles follow a parabolic (curved) path because the horizontal velocity remains constant while the vertical velocity is affected by the acceleration due to gravity (g).
A projectile is an object given an initial velocity and then left to move freely under gravity. Projectiles follow a parabolic (curved) path because the horizontal velocity remains constant while the vertical velocity is affected by the acceleration due to gravity (g). Which launch angle will given the biggest range (the optimum angle)?
1.Resolve the initial velocity into horizontal and vertical components. 2.Use s=d/t to calculate horizontal variables (as there is no acceleration). 3.Use SUVAT equations to calculate vertical variables (as there is acceleration due to gravity). How to approach projectile motion questions: If we assume there is no air resistance there are no forces acting against motion in the horizontal direction therefore (according to Newton’s first law of motion) the ball will continue at the same horizontal speed.
A stunt car drives horizontally off a small cliff with a velocity of 12 m/s. The cliff is 125 m high. How long does the car take to hit the ground? How far from the base of the cliff will the car land? Worked example
Easy example A stone is fired horizontally from a catapult off the top of a building, with a horizontal velocity of 25 m/s. The stone takes 2.5 seconds to hit the ground. what is the height of the building? What is the stones vertical velocity when it hits the ground? How far from the base of the building does the stone hit the ground? Calculate the resultant velocity of the stone as it hits the ground Challenge: If you finish try question 3 pg.144
Questions An object is released from a hot air balloon 50m above the ground which is descending vertically at a speed of 4 ms-1. Calculate: i) the velocity of the object at the ground Ii) the duration of the descent of the object Iii) the height of the balloon above the ground when the object hits the ground Challenge: If you finish try question 3 pg.144
A parcel is released from an aircraft travelling horizontally at a speed of 120 ms -1 above level ground. The parcel hits the ground 8.5s later. Calculate: The height above the ground of the aircraft The horizontal distance travelled in this time by i) the parcel ii) the aircraft The speed of impact of the parcel on the ground
To finish Why is it necessary to fire above a target?