Answer:
Explanation:
Cutting a string in half because
b is irreversible
c is a cheical and d is also a chemical change
Answer:
c. 
Explanation:
= Initial distance between asteroid and rock = 7514 km = 7514000 m
= Final distance between asteroid and rock = 2823 km = 2823000 m
= Initial speed of rock = 136 ms⁻¹
= Final speed of rock = 392 ms⁻¹
= mass of the rock
= mass of the asteroid
Using conservation of energy
Initial Kinetic energy of rock + Initial gravitational potential energy = Final Kinetic energy of rock + Final gravitational potential energy

Answer:
The coupled velocity of both the blocks is 1.92 m/s.
Explanation:
Given that,
Mass of block A, 
Initial speed of block A, 
Mass of block B, 
Initial speed of block B, 
It is mentioned that if the two blocks couple together after collision. We need to find the common velocity immediately after collision. We know that due to coupling, it becomes the case of inelastic collision. Using the conservation of linear momentum. Let V is the coupled velocity of both the blocks. So,

So, the coupled velocity of both the blocks is 1.92 m/s. Hence, this is the required solution.