A kangaroo can jump over an object 2.50 mhigh.

(a) Calculate its vertical speed when it leaves the ground.

(b) How long is it in the air?

Short Answer

Expert verified

a)7ms

b) 1.43 s

Step by step solution

01

Given data

  • Final velocity: V= 0.
  • Distance: D= 2.50 m.
  • Acceleration: g=-9.81 m/s2.
02

Vertical speed or initial velocity of kangaroo

a)

The initial velocity of the kangaroo can be calculated by the following equation:

V2-U2=2gd

Here V is the final velocity, g is the acceleration, U is the initial velocity, and d is the distance traveled to achieve the final velocity.

Substituting the values in the above expression, we get:

02-U2=2×-9.81×2.5U=49.05msU=7ms

Hence the initial velocity of the kangaroo is 7ms.

03

Time taken by a kangaroo in the air

b)

Hence, the given data:

  • U=7ms.
  • V= -7ms.
  • g = -9.81 m/s2

The time can be calculated from the equation of motion as:

V=U+gt

Here t is the time.

Substituting the values in the above expression, we get:

-7=7+-9.81×tt=-14-9.81=1.43s

The total time spent by the kangaroo in the air is 1.43 s .

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