Answer:
Change in potential energy = 7350 Joules
Explanation:
It is given that,
Side of cube, a = 0.5 m
Density of cube, 
The cube is lifted vertically by a crane to a height of 3 m
We know that, density 
So, m = d × V (V = volume of cube = a³)
m = 250 kg
We have to find the change in potential energy of the cube. At ground level, the potential energy is equal to 0.
Potential energy at height h is given by :
PE = 250 kg × 9.8 m/s² ×3 m
PE = 7350 Joules
So, change in potential energy of the cube is 7350 Joules.
Answer:
23.67 km / hr
Explanation:
car travels 355 km (d)
duration = 15 hrs (t)
average speed formula = v = d / t
v = 355 km / 15 hr
v = 23.67 km / hr
The statement ‘Big bang theorists
believe that the universe is expanding and will eventually contract’ is false. The
answer is letter B. The big bang theory suggests that the origin of the
universe began with that exploded and expanded. It also states that the
universe began in a single form of high condensed reactive matter and exploded
forming the galaxies, planets, stars and other celestial bodies.
