Answer:
(a) The horizontal ground reaction force 
(b) The vertical ground reaction force 
(c) The resultant ground reaction force 
Explanation:
Given
John mass , m = 65 kg
Horizontal acceleration , 
Vertical acceleration , 
(a) Using Newton's 2nd law in horizontal direction

=>
Thus the horizontal ground reaction force 
(b) Using Newton's 2nd law in vertical direction

=>
=>
Thus the vertical ground reaction force 
(c) Resultant ground reaction force is

=>
=>
Thus the resultant ground reaction force 
Answer:
C. Increasing its buoyancy
Answer:
I will say that the the potential energy will be at its maximum.
Explanation:
potential energy deals with gravity and gravity deals with height, so when a object is in its maximum height it will have the maximum potential energy.
Answer:
v = 29.4m/s
Explanation:
Since the ball is dropped at rest,
u = 0m/s
a = 9.81m/s²
Using
v = u + at
After 3 seconds,
v = 0 + (9.81)(3)
v = 29.4m/s
Answer:3.67 m/s
Explanation:
mass of block(m)=2 kg
Velocity of block=6 m/s
spring constant(k)=2 KN/m
Spring compression x=15 cm
Conserving Energy
energy lost by block =Gain in potential energy in spring

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