Electric force occurs between positive and negative electric charge. It can be calculated with formula 
where F is force, Q1 and Q2 are charges, A is area of object usually ball (
) because we describe charges as points in space like electrons and protons, 
is a natural dielectric constant of empty space or vacuum (
) and 
also known as relative dielectric variable.
There are two types of the force:
1. Attractive electric force
2. Repulsive electric force
Attractive electric force occurs between positively and negatively charged objects while repulsive occurs between equally charged objects for eg. (positive and positive will repulse).
After the crash the momentum before the crash is equal to the momentum after the crash
Answer:
finding Cepheid variable and measuring their periods.
Explanation:
This method is called finding Cepheid variable and measuring their periods.
Cepheid variable is actually a type of star that has a radial pulsation having a varying brightness and diameter. This change in brightness is very well defined having a period and amplitude.
A potent clear link between the luminosity and pulsation period of a Cepheid variable developed Cepheids as an important determinants of cosmic criteria for scaling galactic and extra galactic distances. Henrietta Swan Leavitt revealed this robust feature of conventional Cepheid in 1908 after observing thousands of variable stars in the Magellanic Clouds. This in fact turn, by making comparisons its established luminosity to its measured brightness, allows one to evaluate the distance to the star.
<h2>
a) Initial velocity = 83 ft/s</h2><h2>
b) Object's maximum speed = 99.4 ft/s</h2><h2>
c) Object's maximum displacement = 153.64 ft</h2><h2>
d) Maximum displacement occur at t = 2.59 seconds.</h2><h2>e)
The displacement is zero when t = 5.70 seconds</h2><h2>
f) Object's maximum height = 153.64 ft</h2>
Explanation:
We have velocity
v(t)= -32t + 83
Integrating
s(t) = -16t²+83t+C
At t = 0 displacement is 46 feet
46 = -16 x 0²+83 x 0+C
C = 46 feet
So displacement is
s(t) = -16t²+83t+46
a) Initial velocity is
v(0)= -32 x 0 + 83 = 83 ft/s
Initial velocity = 83 ft/s
b) Maximum velocity is when the object reaches ground, that is s(t) = 0 ft
Substituting
0 = -16t²+83t+46
t = 5.70 seconds
Substituting in velocity equation
v(t)= -32 x 5.70 + 83 = -99.4 ft/s
Object's maximum speed = 99.4 ft/s
c) Maximum displacement is when the velocity is zero
That is
-32t + 83 = 0
t = 2.59 s
Substituting in displacement equation
s(2.59) = -16 x 2.59²+83 x 2.59+46 = 153.64 ft
Object's maximum displacement = 153.64 ft
d) Maximum displacement occur at t = 2.59 seconds.
e) Refer part b
The displacement is zero when t = 5.70 seconds
f) Same as option d
Object's maximum height = 153.64 ft
Answer:
Work done, W = 0.0219 J
Explanation:
Given that,
Force constant of the spring, k = 290 N/m
Compression in the spring, x = 12.3 mm = 0.0123 m
We need to find the work done to compress a spring. The work done in this way is given by :
W = 0.0219 J
So, the work done by the spring is 0.0219 joules. Hence, this is the required solution.
