Answer:
D. When the box is placed in an elevator accelerating upward
Explanation:
Looking at the answer choices, we know that we want to find out how the normal force varies with the motion of the box. In all cases listed in the answer choices, there are two forces acting on the box: the normal force and the force of gravity. These two act in opposite directions: the normal force, N, in the upward direction and gravity, mg, in the downward direction. Taking the upward direction to be positive, we can express the net force on the box as N - mg.
From Newton's Second Law, this is also equal to ma, where a is the acceleration of the box (again with the upward direction being positive). For answer choices (A) and (B), the net acceleration of the box is zero, so N = mg. We can see how the acceleration of the elevator (and, hence, of the box) affects the normal force. The larger the acceleration (in the positive, i.e., upward, direction), the larger the normal force is to preserve the equality: N - mg = ma, N = ma+ mg. Answer choice (D), in which the elevator is accelerating upward, results in the greatest normal force, since in that case the magnitude of the normal force is greater than gravity by the amount ma.
If the resistance of each bulb is 3 ohms, and they are connected across the battery, then current will flow through them.
In series, the two 3-ohm bulbs will look like a single 6-ohm resistance.
Current = (voltage) / (resistance) = (12v) / (6 ohms) = 2 Amperes.
The battery will need to deliver some power to the circuit.
Power = (voltage) x (current) = (12v) x (2 Amperes) = 24 watts .
Each bulb will dissipate 12 watts, in the form of light and heat.
Do you have a question to ask ?
Answer:
Distance, d = 3242.19 meters
Explanation:
It is given that,
Speed of the dog, v = 19.85 mi/hr
Since, 1 mph = 0.44704 m/s
v = 19.85 mi/hr = 8.873 m/s
Time taken by the dog, t = 6.09 min = 365.4 sec
Let the distance covered by the dog during this time period is d. It can be calculated by the speed of the dog multiplied by the time taken as :
d = 3242.19 meters
So, the the dog travel during this time period is 3242.19 meters. Hence, this is the required solution.
First calculate the time it would take for the crate to
fall using the formula:
h = v0 t + 0.5 g t^2
110 m = 0 + 0.5 (9.8 m/s^2) t^2
t = 4.74 s
The crate is also moving at 46 m/s on with respect to the
horizontal surface, therefore distance covered is:
d = (46 m/s) * 4.74 s
d = 217.95 m
The crate would fall 217.95 m from the tail of the car.
