Cody is using a sling shot and rock to knock down a can that he has placed on a tree stump. His first attempt fails because he r
2 answers:
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Answer:
1000 N
Explanation:
The magnitude of the electrostatic force between two charged object is given by
where
k is the Coulomb constant
q1, q2 is the magnitude of the two charges
r is the distance between the two objects
Moreover, the force is:
- Attractive if the two forces have opposite sign
- Repulsive if the two forces have same sign
In this problem:
are the two charges
r = 3000 m is their separation
Therefore, the electric force between the charges is:
(a) -2451 N
We can start by calculating the acceleration of the car. We have:
is the initial velocity
v = 0 is the final velocity of the car
d = 125 m is the stopping distance
So we can use the following equation
To find the acceleration of the car, a:
Now we can use Newton's second Law:
F = ma
where m = 1100 kg to find the force exerted on the car in order to stop it; we find:
and the negative sign means the force is in the opposite direction to the motion of the car.
(b)
We can use again the equation
To find the acceleration of the car. This time we have
is the initial velocity
v = 0 is the final velocity of the car
d = 2.0 m is the stopping distance
Substituting and solving for a,
So now we can find the force exerted on the car by using again Newton's second law:
As we can see, the force is much stronger than the force exerted in part a).