Can anyone please work out the projectile motion questions?

Question from my paper

1 Answer
Feb 27, 2018

a) v_(0x)=17.809ms^-1
b) y_max=6.318m
c) T=2.271s
d) R=40.446m
e) v_y=-0.6317ms^-1

Explanation:

Given:
Initial velocity of projection: v_0=21ms^-1
Angle of projection theta=32^@

a)
Horizontal component of the initial velocity

v_(0x)=v_0costheta

v_0costheta=21cos32^@

21cos32^@=17.809ms^-1

Thus,

v_(0x)=17.809ms^-1

b) Maximum height reached by the ball

Vertical component of the initial velocity

v_(0y)=v_0sintheta

v_0sintheta=21sin32^@

21sin32^@=11.128ms^-1

v_(0y)=11.128ms^-1

y_max=(v_(0y))^2/(2g)

g=9.8ms^-2

y_max=11.128^2/(2xx9.8)

y_max=6.318m

c) Time of flight of the soccer ball.

initial vertical velocity is

v_(0y)=11.128ms^-1

final vertical velocity is

-v_(0y)=-11.128ms^-1

Change in velocity is

Final velocity - initial velocity

=-11.128-11.128

delv_y=-22.256

Acceleration due to gravity is
g=9.8ms^-2

Acceleration during the journey is

a_y=-9.8

Time of flight is

T=(delv_y)/a_y=-22.256/-9.8

T=2.271s

d) Range of the soccer ball

Acceleration along horizontal direction is zero

R=v_(0x)T

v_(0x)=17.809ms^-1

T=2.271s

R=17.809xx2.271

Range of the soccer ball is

R=40.446m

e) Velocity of the soccer ball after time t = 1.2 s

v_x=v_(0x)
Same for the entire journey

v_y=v_(0y)+a_yt

v_y=11.128+(-9.8)t

v_y=11.128-9.8t

Substitute t=1.2s

v_y=11.128-9.8xx1.2

v_y=-0.6317ms^-1