Answer:
2.62seconds
Explanation:
Speed is defined as the ratio of the distance covered by a body with respect to time.
Speed v = Distance (s)/Time (t)
For a traveling sound wave, the distance between the source of a sound and the reflector is '2S'.
Speed v = 2 × distance (S)/Time (T)
V = 2S/t
2S = vt
Given speed of the wave = 342m/s
Distance covered = 450m
t = 2S/v
t = (2×450)/343
t = 900/343
t = 2.62seconds
It will take him 2.62seconds for him to hear his own voice echo off of the wall.
First introduce yourself. Start talking to him little by little. Compliment him, that’ll help. Make some jokes, and talk about stuff he is interested in. Make conversation. Try not to be overbearing.
Answer:
6666.67 Newtons
Explanation:
The formula F=ma (force is equal to mass multiplied by acceleration) can be used to calculate the answer to this question.
In this case:
- mass= 0.1mg= 1*10^-7 kg
- velocity= 4.00*10^3 m/s
- time= 6.00*10^-8 s
Using velocity and time, acceleration can be calculated as:
Substituting these values into the formula F=ma, the answer is:
- F= (1*10^-7)kg * (6.667*10^10) m/s²
- F= 6666.67 Newtons of force
Answer:
581 kJ, work was done by the system
Explanation:
According to the first law of thermodynamics:

where
is the change in internal energy of the system
Q is the heat absorbed by the system (positive if absorbed, negative if released)
W is the work done by the system (positive if done by the system, negative if done by the surrounding)
In this problem,


Therefore the work done by the system is

And the positive sign means the work is done BY the system.
Answer:
Acceleration will increase.
Explanation:
The relation between force, mass and acceleration according to the Newton's second law of motion is given as:
F = ma
We are given that the driving force on the truck remains constant, so F is constant here. We can rewrite the above equation as:

Since, F is constant, the acceleration of the truck is inversely proportional to the mass.
There is a hole at the bottom of the truck through which the sand is being lost at a constant rate. Since, the sand is being lost, the overall mass of the truck is being reduced.
Since, the acceleration of the truck is inversely proportional to the mass, the reduced mass will result in an increased acceleration.
So, the acceleration of the truck will increase.