1a.When a bus suddenly starts, the passengers sitting or standing in the bus tend to fall backward. This is due to inertia of rest and can be explained as follows: when the bus suddenly starts, the lower part of the body of the passenger which is in contact with the bus moves along with the bus while the upper part of the body tends to retain its state of rest due to inertia. As a result, the passenger falls backward.
2a.When moving bus suddenly stops, the passengers sitting or standing in the bus are thrown forward. This is due to inertia of motion and can be explained as follows: when the moving bus suddenly stops, the lower part of the body of the passenger contact with the bus suddenly comes to rest while the upper part of the body tends to retain its state of motion due to inertia. As a result, the passenger is thrown forward.
3a.When a person jumps out of a moving vehicle, he falls forward due to inertia of motion.
1b.When you kick a ball, you exert force in a specific direction, which is the direction in which it will travel.In addition, the stronger that ball is kicked, the stronger the force we put on it and the further away it will go.
2b.<span>Professional athletes move their hands back once they catch the ball as it provides the ball more time to lose its speed, and in turn apply less force on its part.
</span>3b.<span>In a golf game, the acceleration of the ball is directly proportional to the force applied to the club and inversely proportional to its mass. In the way influences the force of the air that can cause a small change in its direction.</span>
Answer:
a) 0 Nm b) mgL/2 Nm counterclockwise
Explanation:
Before we even begin answering the question, we have to appreciate the fact that the weight of the constant density symmetrical rigid objects is considered to be acting from its geometrical center, which we will call the center of mass. If the clock arm is considered to be rectangular , rigid and constant density(assumed, since this is a high school question) we can proceed with our analysis. We also note that the torque on the arm are given by,
where m is the total mass of the arm , x is the horizontal distance(perpendicular to the direction of force) of the center of mass of the arm from the center of the clock and g is the acceleration due to gravity. Also let L be the length of the hour arm.
In part a) the horizontal distance of the center of mass of the arm from the center of the clock would be zero since at noon the center of mass of the clock arm is right above the center of the clock. So x = 0 , hence T = 0 Nm.
in part b) the horizontal distance between the center of mass of the arm and the center of the clock is L/2 , where L is the length of the hour arm , but the weight acts from half that distance since the weight of the object is considered to be acting from the geometrical center of the object which in this case is L/2 distance away from the center of the clock. So plugging into the above equation we get T = mg*(L/2) Nm, the force acting downwards from the left since the arm is pointing at 9:00 , which will result in a counter clockwise torque. So T=mgL/2 Nm counter clockwise is the Torque due to the hour arm.
If you already know calculus you can check the answer to part b) by evaluating the integral,
where M is the mass per unit length of the arm. m is the total mass given by m=ML.
You have
1
s
, and oftentimes with wavelength, you want to convert to
nm
which is UV-Vis range (
200~700 nm
), and is often of spectral interest.
What you want to do is:
1
s
→
1
m
→
m
→
nm
Conversion factors are extremely useful, and one easy one to remember is the speed of light, which is about
3
×
10
8
m/s
.
1
1
s
⋅
s
m
=
m
And finally, we can convert to
nm
:
10
9
nm
=
1 m
→
conversion factor:
10
9
nm
1 m
m
⋅
10
9
nm
1
m
Thus, overall, you just have:
nm
=
1
1
s
⋅
s
3
×
10
8
m
⋅
10
9
nm
1
m
=
1
1
/
s
⋅
3
×
10
8
m
/
s
×
10
9
nm
1
m
here the answer to your question hope it helps you
electric circuit
Atoms family is molecules or a tv shoe