Answer:
2.85 s .
Explanation:
y(t) = y(0) + v₀t + 1/2 gt²
y(t) is vertical displacement , y(0) is initial position , v₀ is initial velocity and t is time required to make vertical displacement and g is acceleration due to gravity.
Here y(0) is zero , v₀ = 14 m/s , g = 9.8 m s⁻² , y(t ) = 0 , as the pumpkin after time t comes back to its initial position, that is ground .
We shall take v₀ as negative as it is in upward direction and g as positive as it acts in downward direction
Put the values in the equation above,
0 = 0 - 14t + 1/2 x 9.8 t²
14 t = 1/2 x 9.8 t²
t = 28 / 9.8
t = 2.85 s .
Answer:
3Q / 4 pi (R^3 - r^3)
Explanation:
Charge density = charge / volume
volume of a spherical shell = 
So what we can do is apply the<span> Hooke's law wich states that
F = -kx ( P.S the -ve sign means opposite in direction )
Also we will need to determine the spring's constant with the formula:
k = F / x
Where F = the force ( = 20 N )
x = the displacement of the end of the spring from it's position ( = 0.20 m )
k = the spring's constant ( = unknown )
So this would be: k = 20 / 0.20 = 100 N/m
The period of oscillation of 4 kg : T = 2 * pi * square root m / k
T = 2 * pi * square root 4 / 100
T = 1.256 seconds
Hope it helps</span>
