Answer:

Explanation:
Average velocity is defined as the ratio of total displacement of the motion and total time taken in that motion
here we know that initially the sky diver drops without opening parachute by total displacement 625 m
then she open her parachute and drop another 362 m
so first it took time t = 15 s to drop without open parachute
then it took t = 139 s to drop next displacement
so here total displacement is given as

total time is given as

so average velocity is given as


Answer:
Force = -91.7 Newton
Explanation:
Given the following data;
Mass = 47 kg
Time = 4.1 seconds
Initial velocity = 8 m/s
Since the object comes to a stop, its final velocity would be equal to zero.
To find the force required to bring it to stop;
First of all, we would determine the acceleration of the object;
Mathematically, acceleration is given by the equation;

Substituting into the equation;
Acceleration, a = -1.95 m/s²
Next, we would determine the force required to bring the object to stop;
Force = -91.65 ≈ 91.7 Newton
Answer:
v₀ = 15 m/s
Explanation:
given,
initial velocity = v₀
down acceleration of rock = 10 m/s²
rock distance
S₄ = 7 x S₁
From kinematic equations
S = v₀ t+0.5 at²
at t = 1 s
S₁ = v₀ (1)+0.5 x 10 x 1²
S₁ = v₀+ 5......(1)
at t = 4 s
S₄ = v₀ (4)+0.5 x 10 x 4²
S₄ = 4 v₀+80.....(2)
from equation (1) and (2)
7( v₀ + 5 ) = 4 v₀ +80
3 v₀ = 80 - 35
3 v₀ = 45
v₀ = 15 m/s
Answer:
The kinetic energy at ground will be "238.2 J".
Explanation:
The given values are:
mass,
m = 3 kg
Initial height,
h = 3 m
Initial velocity,
v = 10 m/s
By using the conservation of energy at points A and B,
⇒ 
⇒ 
On substituting the values, we get
⇒ 
⇒ 
⇒ 
⇒ 