An arrow is shot straight up in the air with speed of 20m/s. How long is t in the air? How high will the arrow rise?

User Icon for Damon Damon answered
14 years ago

F = m a

F = -mg
so a = -g = -9.8
v = Vo -9.8t
0 at top = 20 - 9.8 t
t at top = 20/9.8 (same time falling so double that for time in air)
at t = t at top. how high is it?
h = 20 t - (1/2) (9.8) t^2

User Icon for Jake Jake answered
14 years ago

amm i got an answer of 4.08 for the time in the air I divided 20/9.8=2.04x2=4.08

For the rise I do not multiply by 2 t right? I got answer of 20.4

I am very glad that you were able to help me with this problem

User Icon for Step-by-Step Bot Step-by-Step Bot answered
1 year ago

To find the time the arrow is in the air, we can use the equation:

t = (2 * v) / g

where t is the time, v is the initial velocity, and g is the acceleration due to gravity (approximately 9.8 m/s²).

Substituting the given values, we have:

t = (2 * 20 m/s) / 9.8 m/s²
t = 2.04 seconds

Therefore, the arrow is in the air for approximately 2.04 seconds.

To find the maximum height the arrow will reach, we can use the equation:

h = (v²) / (2 * g)

where h is the maximum height.

Substituting the given values, we have:

h = (20 m/s)² / (2 * 9.8 m/s²)
h = 204 / 19.6
h ≈ 10.41 meters

Therefore, the arrow will rise to a maximum height of approximately 10.41 meters.

User Icon for Explain Bot Explain Bot answered
1 year ago

To determine how long the arrow is in the air, we can use the fact that the initial vertical velocity when the arrow is shot up is 20 m/s, and the final vertical velocity when the arrow reaches the highest point is 0 m/s.

The time it takes for the arrow to reach its highest point can be found using the equation for vertical motion:

v(final) = v(initial) + (acceleration * t),

where v(final) is the final velocity, v(initial) is the initial velocity, acceleration is the acceleration due to gravity (approximated as 9.8 m/s²), and t is the time taken.

In this case, we have:

0 m/s = 20 m/s + (-9.8 m/s² * t).

By rearranging the equation, we can solve for t:

-20 m/s = -9.8 m/s² * t.

Dividing both sides of the equation by -9.8 m/s² yields:

t = 20 m/s / 9.8 m/s²,
t ≈ 2.04 seconds.

So, the arrow will be in the air for approximately 2.04 seconds.

To determine how high the arrow will rise, we can use the equation for vertical displacement during uniform acceleration:

s = v(initial) * t + (1/2) * acceleration * t²,

where s is the displacement (height), v(initial) is the initial velocity, acceleration is the acceleration due to gravity, and t is the time taken.

Plugging in the given values:

s = 20 m/s * 2.04 s + (1/2) * (-9.8 m/s²) * (2.04 s)²,

s ≈ 20.4 m.

Therefore, the arrow will rise to a height of approximately 20.4 meters.