In which situation is the object experiencing unbalanced forces? A) A box resting on a horizontal floor. B) A car slowing as it
2 answers:
Answer:
B) A car slowing as it reaches a traffic light.
Explanation:
Newton's second law states that an object which experiences unbalanced forces has an acceleration, according to the equation:
where
F is the net force acting on the object
m is its mass
a is its acceleration
When the forces are unbalanced, it means that the net force F is different from zero, so the acceleration of the object (a) is also different from zero.
Now let's analyze each situation:
A) A box resting on a horizontal floor. --> The object is at rest, so it is not accelerating. This means that the forces acting on it are balanced (net force = 0), so this is not the correct choice
B) A car slowing as it reaches a traffic light. --> The car is slowing down, this means that it has an acceleration: therefore, it is experiencing unbalanced forces. So, this is the correct choice.
C) A car with its cruise control set to 30 km/h. --> The car is moving at constant velocity, so it has zero acceleration. This means that the forces acting on it are balanced (net force = 0), so this is not the correct choice
D) A penny at terminal velocity after falling off of a building. --> The penny is at terminal velocity, which means that it is moving at constant velocity, so it has zero acceleration. This means that the forces acting on it are balanced (net force = 0), so this is not the correct choice.
Therefore, the correct choice is
B) A car slowing as it reaches a traffic light.
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<h2>Answer:</h2>
1.99 x 10⁶C
<h2>Explanation:</h2>The electrical energy () stored in the battery will give the car some kinetic energy (
) which will cause the car to move from rest to some other point.
i.e
=
------------------(i)
<em>But;</em>
=
x Q x V; -------------------(ii)
Where;
Q = charge on the battery
V = potential difference or voltage of the battery = 12.0V
<em>Also</em>
= (
x m x v²) - (
x m x u²) -----------------(iii)
Where;
m = mass of the car = 956kg
v = final velocity of the car = 158m/s
u = initial velocity of the car = 0 [since the car starts from rest]
<em>Substitute equations (ii) and (iii) into equation (i) as follows;</em>
x Q x V = (
x m x v²) - (
x m x u²) -----------------(iv)
<em>Substitute all necessary values into equation (iv) as follows;</em>
x Q x 12.0 = (
x 956 x 158²) - (
x 956 x 0²)
x Q x 12.0 = (
x 956 x 158²) - (0)
x Q x 12.0 = (
x 956 x 158²)
x Q x 12.0 = 11932792
6Q = 11932792
<em>Solve for Q;</em>
Q = 11932792 / 6
Q = 1988798.67 C
Q = 1.99 x 10⁶C
Therefore, the amount of charge the batteries must have is 1.99 x 10⁶C
Answer:
Explanation:
I1 = 3 A right
I2 = 6.8 A left
Let the distance is r from both the wires on the same side.
The formula for the magnetic field is given by
As the direction of current in both the wires is opposite to each other
so the net magnetic field is
B = B2 - B1