Answer:
Explanation:
Given
time of contact between bat and ball is 
suppose u is the incoming velocity and v is the final velocity after collision

Impulse exerted is given by change in momentum of the particle.
Initial momentum 
Final momentum 
Change in momentum 
Impulse 


Answer: They will repel each other.
Explanation:
Two inflated balloons when rubbed with woolen cloth will lead to repeal each other because of the similar charges on both the balloons.
Rubbing both the balloons together by the woolen cloth will introduce negative charge in the balloons.
As, we know that the same charges repeal each other both of the balloons with be apart from each other.
This is due to the static electricity, the negatively charged particles jump to the positive one. When balloons are rubbed they become negatively charged.
Answer: a good level of body fat can be found using your weight and height as a reference.
Explanation:
How bright a star appears from Earth is the star's apparent magnitude.
Answer:
v' = 1.5 m/s
Explanation:
given,
mass of the bullet, m = 10 g
initial speed of the bullet, v = 300 m/s
final speed of the bullet after collision, v' = 300/2 = 150 m/s
Mass of the block, M = 1 Kg
initial speed of the block, u = 0 m/s
velocity of the block after collision, u' = ?
using conservation of momentum
m v + Mu = m v' + M u'
0.01 x 300 + 0 = 0.01 x 150 + 1 x v'
v' = 0.01 x 150
v' = 1.5 m/s
Speed of the block after collision is equal to v' = 1.5 m/s