Answer:
-4.0 N
Explanation:
Since the force of friction is the only force acting on the box, according to Newton's second law its magnitude must be equal to the product between mass (m) and acceleration (a):
(1)
We can find the mass of the box from its weight: in fact, since the weight is W = 50.0 N, its mass will be
And we can fidn the acceleration by using the formula:
where
v = 0 is the final velocity
u = 1.75 m/s is the initial velocity
t = 2.25 s is the time the box needs to stop
Substituting, we find
(the acceleration is negative since it is opposite to the motion, so it is a deceleration)
Therefore, substituting into eq.(1) we find the force of friction:
Where the negative sign means the direction of the force is opposite to the motion of the box.
Answer:
The number of crates is 84580.
Explanation:
mass, m = 30 kg
height, h = 0.9 mm
Power, P = 0.5 hp = 0.5 x 746 W = 373 W
time, t = 1 minute = 60 s
Let the number of crates is n.
Power is given by the rate of doing work.
Distance = (30+40+50) = 120 km
It's back where it started, so displacement = zero
Answer:
Flutter
Explanation:
Flutter is a type of arrhythmia that causes very fast and regular ryth of the atria of about 250 beats per minute.
Arrhythmia can be defined as any sort of irregularity heart rate or rhythm is also called as dysrhythmia.
Arrhythmias can be categorized as heart block, bradycardia, tachycardia, fibrillation, flutter, sick sinus syndrome, and is diagnosed by Electrocardiography.
In Flutter, the heart chambers do get sufficient time to get filled with blood completely prior to next contraction.
Answer:
the answer the correct one is c
Explanation:
Electric charges of different signs attract and those of the same sign repel. In addition, there are two types of insulating bodies, where the loads are fixed (immobile) and metallic (with mobile loads.
Let's analyze the situation presented
* A rod with positive approaches and the sphere is attracted, so the charge on the sphere is negative
* A rod with a negative charge approaches and the sphere is attracted, therefore the charge of the sphere must be positive.
For this to happen, the sphere must be unloaded and the charge that creates the phenomenon are induced charges because the mobile charges of the same sign as the sphere are repelled.
when checking the answer the correct one is c
