An object is falling from a height of 7.5 meters. At what height will its velocity be 7 meters/second?

A. 49 meters
B. 7.5 meters
C. 7.0 meters
D. 5.0 meters
E. 2.5 meters

Question

An object is falling from a height of 7.5 meters. At what height will its velocity be 7 meters/second?

A. 49 meters
B. 7.5 meters
C. 7.0 meters
D. 5.0 meters
E. 2.5 meters

anonymous · Answer

according the formula 

$$v ^{2}=v _{0}^{2}+2as$$

$$v=7 m/s$$
$$v _{0}=0 m/s$$
$$a=9.8 m/s^{2}$$

the value of 
$$s=2.5m$$
then
$$7.5m-2.5m=5m$$

so the answer is D

anonymous · Answer

Apply Equation of Motion.

$$V^{2} = U^{2} + 2as$$

(7)^2 = 2 * g * s1
g = gravitational constant

s1 = 49/2g

Distance from the ground = 7.5- 49/2g =