A particle moves along the x-axis according to x(t)=10t−2t²m. (a) What is the instantaneous velocity at t = 2 s and t = 3 s? (b)
1 answer:
Answer:
a) v(2) = 2m/s, v(3) = -2m/s
b) speed at t = 2s is 2m/s
speed at t = 3s is 2m/s
c) 0 m/s
Explanation:
We can take the derivative of x(t) to find the equation of velocity
v(t) = x'(t) = 10 - 4t
(a) v(2) = 10 - 4*2 = 10 - 8 = 2 m/s
v(3) = 10 - 4*3 = 10 - 12 = -2 m/s
(b) The speed would be the same as velocity without the direction
speed at t = 2s is 2m/s
speed at t = 3s is 2m/s
(c) The average velocity between t = 2s and t = 3s is distance it travels over period of time
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Answer:
The correct answer is A
Explanation:
The question requires as well the attached image, so please see that below.
Coulomb's Law.
The electrical force can be understood by remembering Coulomb's Law, that describes the electrostatic force between two charged particles. If the particles have charges and
, are separated by a distance r and are at rest relative to each other, then its electrostatic force magnitude on particle 1 due particle 2 is given by:
Thus if we decrease the distance by half we have
So we get
Replacing we get
We can then multiply both numerator and denominator by 4 to get
So we have
Thus if we decrease the distance by half we get four times the force.
Then we can replace the second condition
So we get
which give us
Thus doubling one of the charges doubles the force.
So the answer is A.
