Answer:
"The distance between crests is 3 cm."
Explanation:
If he writes down "The distance between crests is 3 cm."
That means he is describing the wavelength of a wave and not longitudinal wave. He ought to write something about " direction "
Longitudinal waves are waves in which the displacement of the medium is in the same direction as, or parallel to, the direction of propagation of the wave. While
Wavelength is the distance between the two successfully Crest or trough
Given:
Mass (m) = 1200 kg
Distance (s) = 100 m
Time (t) = 10 seconds
Now,

=

= 10 m/s
<span><u>
Note that this one is the final velocity.</u></span><u />
We also know that,
initial velocity (u) = 0 m/s .......<span>
because the car starts from rest.</span>Now,

=

=

= 1 m/s²
Now,
Force (F) = mass (m) * acceleration (a)
= 1200 kg * 1 m/s²
= 1200 kg.m/s²
= 1200 N
Now,
Work Done (W) = Force (F) * displacement (s) ....<span>
note that displacement is same as distance.
</span><span> = 1200 N * 100 m
</span> = 120000 N.m
= 120000 J
Now,
Power (P) =

=

= 12000 J/s
= 12000 watt
SO,
A) The acceleration of the car is 1 m/s².
B) 1200 Newton (N) force must have acted on the car.
C) The velocity of the car after 10 seconds is 10 m/s.
D) 120000 Joule (J) work was done on the car. E) The engine produced a minimum power of 12000 watt.
Answer:
v = 5.75 x 10⁶ m/s
Explanation:
The radius (r) of the circular orbit taken by a charged particle is related to its speed perpendicular to a magnetic field of strength B, and is given by
r =
--------------(i)
Where,
q = charge of the particle
m = mass of the particle
Making v subject of the formula in equation (i) above gives
v =
-------------------(ii)
Given;
r = 20cm = 0.2m
B = 0.3T
v = unknown
q = charge of proton = 1.6 x 10⁻¹⁹ C
m = mass of the proton = 1.67 x 10⁻²⁷kg
Substitute the values of m, q, B and r into equation (ii) above to get;
v = 
Solving for v gives:
v = 5.75 x 10⁶ m/s
Therefore, the velocity of the proton is 5.75 x 10⁶ m/s