J=joules, c=specific heat, q= energy, and the Tf and Ti are the final and initial temperatures cause I couldn't find a delta sign.
Velocity is speed plus the direction of the speed.
Acceleration is the
rate of change of velocity, a body moving with uniform velocity does not
possess acceleration at all i.e. acceleration is zero
Answer:
a)
& 
b) 
c) 
Explanation:
Given:
mass of the book, 
combined mass of the student and the skateboard, 
initial velocity of the book, 
angle of projection of the book from the horizontal, 
a)
velocity of the student before throwing the book:
Since the student is initially at rest and no net force acts on the student so it remains in rest according to the Newton's first law of motion.

where:
initial velocity of the student
velocity of the student after throwing the book:
Since the student applies a force on the book while throwing it and the student standing on the skate will an elastic collision like situation on throwing the book.

where:
final velcotiy of the student after throwing the book
b)



c)
Since there is no movement of the student in the vertical direction, so the total momentum transfer to the earth will be equal to the momentum of the book in vertical direction.



Answer:
According to the Newton's law of gravitational every object in the universe attracts every other objects with a force which is called gravitational force.This gravitational force is (i) directly proportional to the product of their masses and (ii) inversely proportional to the square of the distance between their centres.
Explanation:
Newton's law of gravitational is called the universal law because it is applicable to all the bodies either terrestrial or celestial having any shape,size,mass or at any distance apart with any medium between them,at any time(past,present or future).