D ............................
Answer: The spring constant is K=392.4N/m
Explanation:
According to hook's law the applied force F will be directly proportional to the extension e produced provided the spring is not distorted
The force F=ke
Where k=spring constant
e= Extention produced
h=2m
Given that
e=20cm to meter 20/100= 0.2m
m=100g to kg m=100/1000= 0.1kg
But F=mg
Ignoring air resistance
assuming g=9.81m/s²
Since the compression causes the plastic ball to poses potential energy hence energy stored in the spring
E=1/2ke²=mgh
Substituting our values to find k
First we make k subject of formula
k=2mgh/e²
k=2*0.1*9.81*2/0.1²
K=3.921/0.01
K=392.4N/m
Answer:
285 seconds
Explanation:
Jenny speed is 3.8 m/s
Alyssa speed in 4.0 m/s
Alyssa starts after 15 seconds
Find the distance covered by Jenny, when Alyssa starts
Distance=Speed*time
Distance covered by Jenny in 15 seconds= 3.8×15=57m
Relative speed of the two members heading same direction will be;
4.0m/s-3.8m/s=0.2m/s
To find the time Alyssa catch up with Jenny you divide the distance to be covered by Alyssa by the relative speed of the two
Distance=57m, relative speed=0.2m/s t=57/0.2 =285 seconds
=4.75 minutes
Answer:height above ground at which projectile have velocity
0.5v is (0.0375v^2)
Explanation:
Using Vf = Vi - gt
Where Vf is final velocity
Vi is initial velocity
g is the acceleration due to gravity
t is the time taken
So, 0.5v = v - gt
t = 0.05v
Therefore height h = vt - 0.5gt^2
Subtitute t
h = 0.05v^2 - 0.0125v^2
h = 0.0375v^2
