Earths atmosphere, Temperature, Plant life and Oxygen I guess
Answer
given,
vertical speed of stone,v = 12 m/s
height of the cliff = 70 m
a) time taken by the stone to reach at the bottom of the cliff
We know that,
S = u t + 1/2 a t²
- 70 = 12 t - 0.5 x 9.8 t²
4.9 t² - 12 t - 70 = 0
solving the equation
t = 5.2 s (neglecting the negative value)
b) again using equation of motion
v = u + a t
v = 12 - 9.8 x 5.2
v = -38.96 m/s
ignoring the negative sign
magnitude of velocity is equal to 38.96 m/s
c) total distance travel by the stone
vertical distance covered by the stone
v² = u² + 2 g h
0 = 12² - 2 x 9.8 x h
h = 7.34 m
to reach the stone to the same level distance travel be doubled.
Total distance travel by the stone
H = h + h + 70
H = 7.34 x 2 + 70
H = 84.7 m.
Answer:
t = 1.659s
Explanation:
We can use the kinematics equations to solve this questions:
v = u + at
where v = Final Velocity, u = initial velocity, a = acceleration, t = time, s = displacement
a) Given information from the question,
u = 
(Convert km/h to m/s first)
a = 
s = 35m
Now we can substitute these values into the 2nd kinematics equation to find v, final velocity.
b) Now we have the final velocity, we can substitute the values into the first kinematics equation to find t , the time taken.
v = u + at
22.761 = 19.444 + 2t
2t = 22.761 - 19.444
t =
t = 1.659s
The last choice is correct, in order to have kinetic energy a object must be in motion, if not then the object has no kinetic energy
