Hubble noticed that the galaxies were moving away from us, which meant the universe was expanding.
This is why constellations change over time. In some years, the Big Dipper won't actually look like a dipper anymore.
Answer:

Explanation:
We have:
diameter of the wheel, 
weight of the wheel, 
mass of hanging object to the wheel, 
speed of the hanging mass after the descend, 
height of descend, 
(a)
moment of inertia of wheel about its central axis:




Answer:

Explanation:
From the conservation of mechanical energy




Solve to velocity v2




The force acting on the cart is 1.43 N.
<h3>What is force?</h3>
Force can be defined as the product of mass and acceleration.
To calculate the force acting on the cart, we use the formula below.
Formula:
- F = m(v-u)/t................. Equation 1
Where:
- F = Force acting on the cart
- m = mass of the cart
- v = Final velocity
- u = initial velocity
- t = time
From the question,
Given:
- m = 500 g = 0.5 kg
- v = 30 m/s
- u = 10 m/s
- t = 7 seconds
Substitute these values into equation 1
- F = 0.5(30-10)/7
- F = 10/7
- F = 1.43 N.
Hence, the force acting on the cart is 1.43 N.
Learn more about force here: brainly.com/question/13370981