contestada

A toy rocket launcher can project a toy rocket at a speed as high as 35.0 m/s.
(a) If air resistance can be ignored, how high (in m) would a toy rocket launched at this speed rise if projected straight up?
(b) How long would the toy rocket be in the air (in s)?

Respuesta :

Answer:

(a) 62.5 m

(b) 7.14 s

Explanation:

initial speed, u = 35 m/s

g = 9.8 m/s^2

(a) Let the rocket raises upto height h and at maximum height the speed is zero.

Use third equation of motion

[tex]v^{2}=u^{2}+2as[/tex]

[tex]0^{2}=35^{2}- 2 \times 9.8 \times h[/tex]

h = 62.5 m

Thus, the rocket goes upto a height of 62.5 m.

(b) Let the rocket takes time t to reach to maximum height.

By use of first equation of motion

v = u + at

0 = 35 - 9.8 t

t = 3.57 s

The total time spent by the rocket in air = 2 t = 2 x 3.57 = 7.14 second.

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