Question

1. An airow is shot horizontally from a crossbow 1.5 m above the ground. The initial velocity is 45

m/s. How long will the arrow travel through the air before hitting the ground?

Answer 1

Time taken by the arrow to travel along to hit the ground is 0.55 seconds.

Step-by-step explanation:

The only "force" acting on the "crossbow" to cause it to "hit" the ground is "gravity". There is no initial velocity downward when it shoot.

`d=v_(i) t+(1)/(2) t^(2)`

d = the displacement of the object

t = the time for which the object moved

a = acceleration of the object

`v_i` = the initial velocity of the object

Given values

d = 1.5 m

t = unknown

`a=g=9.8 \mathrm{m} / \mathrm{s}^(2)`

`\mathrm{V}_{\mathrm{i}}=0 \mathrm{m} / \mathrm{s}`

`1.5 \mathrm{m}=0(\mathrm{t})+(1)/(2)\left(9.8 \mathrm{m} / \mathrm{s}^(2)\right) \mathrm{t}^(2)`

`1.5=0+4.9 \mathrm{t}^(2)`

`\mathrm{t}^(2)=(1.5)/(4.9)`

`t^(2)=0.306 \mathrm{s}`

Square root both sides

`t=√(0.306)`

t = 0.55 s