A1.2-kg mass is projected from ground level with a velocity of 30 m/s at some unknown angle above the horizontal. a short time after being projected, the mass barely clears a 16-m tall fence. disregard air resistance and assume the ground is level. what is the kinetic energy of the mass as it clears the fence

= 351.84 J

Explanation:

Using the conservation of energy K:

so:

where m is the mass, v the initial velocity, is the kinetic energy of the mass as it clears the fence, g the gravity and h the altitude.

Then, replacing values, we get:

solving for :

= 351.84 J

electrical power

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s