D=at²
441m=(5*9.81m/s²)(t²)
t²=441/(5*9.81)
t≈√8.99
t≈3 sec
Answer:Racquet force is twice of Player force
Explanation:
Given
ball arrives at a speed of 
ball returned with speed of 
average Force imparted by racquet on the ball is given by

where 
time of contact of ball with racquet


When it land on the player hand its final velocity becomes zero and time of contact is same as of racquet


From 1 and 2 we get

Hence the magnitude of Force by racquet is twice the Force by player
The density of ice is less than the density of water. C
Answer:
(a) A = m/s^3, B = m/s.
(b) dx/dt = m/s.
Explanation:
(a)

Therefore, the dimension of A is m/s^3, and of B is m/s in order to satisfy the above equation.
(b) 
This makes sense, because the position function has a unit of 'm'. The derivative of the position function is velocity, and its unit is m/s.
Answer:
0 m/s
Explanation:
Average velocity of an object is given by the net displacement divided by time taken. Displacement is equal to the shortest path covered by the object.
In this problem, a player runs the length of the 30-meter court and back. The player does this three times in 60 seconds.
As the player runs the court and returns to the original point. It would mean that the shortest path covered is 0.
Average velocity = displacement/time
v=0/30
v = 0 m/s
Hence, the correct option is (1).