Explanation:
<em>The absolute threshold of hearing is the minimum sound level of a pure tone that an average human ear with normal hearing can hear with no other sound present. The absolute threshold relates to the sound that can just be heard by the organism.</em>
Answer:
735watts
Explanation:
Power = Force*distance/time
Given
Force = mg = 50 * 9.8'
Force = 490N
distance = 3m
time = 2s
Substitute
Power = 490*3/2
Power = 1470/2
Power = 735Watts
Hence the minimum power output is 735watts
Answer:
B = 6.18 10⁻⁶ T
the magnetic field is in the negative direction of the y axis
Explanation:
The magnetic force is given by
F = q v x B
as in the exercise indicate that the velocities perpendicular to the magnetic field,
F = q v B
Newton's second law is
F = m a
let's substitute
q v B = m a
B = m a / q v
let's calculate
B = 9.1 10⁻³¹ 2.50 10¹³ / (1.6 10⁻¹⁹ 2.30 10⁷)
B = 6.18 10⁻⁶ T
The direction of the field can be obtained with the right hand rule, where the thumb points in the direction of the velocity, the fingers extended in the direction of the magnetic field and the palm in the direction of the force for a positive charge.
In the exercise indicate that the velocity is the z axis
the acceleration and therefore the force in the x axis
therefore the magnetic field is in the negative direction of the y axis
The acceleration exerted by the object of mass 10 kg is 
Answer: Option A
<u>Explanation:</u>
According to Newton’s second law of motion, any external force acting on a body will be directly proportional to the mass of the body as well as acceleration exerted by the body. So, the net external force acting on any object will be equal to the product of mass of the object with acceleration exerted by the object. Thus,

So,

As the force acting on the object is stated as 10 N and the mass of the object is given as 10 kg, then the acceleration will be

So, the acceleration exerted by the object of mass 10 kg is 
Answer:
7,166 hrs =430 minutes
Explanation:
Since both train are on the same track, going one towards the other, the relative speed is the addition of both, then the time they need to meet, and consistently crash, is the time that (65mph + 55 mph)=120mph need to travel the total distance of 860 miles, of course in this case one part is traveled by the first train and the rest by the other. Then to find the time we use a three rule
1 h --->120mi
X ---->860mi, then X=(860 mi* 1h)/120 mi = 43/6 hrs= 7,16666 hrs, turning this into minutes need that we notice 1h=60min, then 43/6 hrs *60 min/hrs = 430 minutes.