Answer:
Sound is a vibration, or wave, that travels through the air. Sound waves are invisible to our eyes; unless we find a way to make the sound waves move something that we can see. In this activity, your child will use different noise-making objects to cause sound waves and make sand visibly move.
Sound wave can be described by five characteristics: Wavelength, Amplitude, Time-Period, Frequency and Velocity or Speed. The minimum distance in which a sound wave repeats itself is called its wavelength.
Explanation:
When the vibrating air hits your eardrum, it causes your eardrum to vibrate, just as the balloon did. These vibrations are transferred through the tiny bones in your ear to the inner ear. These vibrations are detected by nerves, which send impulses that your brain "hears" as sound.
Answer:
Explanation:
The impulse-momentum theorem states the impulse on an object is equal to the change in momentum of that object. Momentum is given by 
. Since mass is constant, the train's change in momentum is:
(two significant figures).
Impulse is also given as 
, where 
is the average force applied and 
is change in time. Since 
is given as 
, we have the following equation:
(two significant figures).
Answer:
The correct answer is c
Explanation:
Flow is defined by
Ф = B . A
bold letters indicate vectors.
The magnetic field is directed to the y axis, The area of the coil is represented by a vector normal to the plane of the coil, so to have a flux
i.i = j.j = k.k = 1
and the tori scalar products are zero
a) If the coil must be in the xy plane so that its normal vector is in the Z axis, so there is no flux
b) if the coil is in the plane yz the normal veto is in the x axis, so the flux is zero
C) If the coil is in XZ, the normal vector points in the y direction, usually the scalar product is one and there is a flux in this configuration
The correct answer is c
Answer:
15 N
Explanation:
The magnetic force on a piece of current-carrying wire is given by:
where
I is the current in the wire
L is the length of the piece of wire
B is the magnetic field strength
is the angle between the direction of B and I
In this problem:
I = 10 A
B = 0.3 T
L = 5 m
Substituting into the equation, we find
