It takes the car 14 seconds to stop
Explanation:
A car is traveling at a constant velocity of 19 m/s when the driver puts
on the brakes to accelerate it at -1.4 m/s² until stopped
1. The initial velocity is 19 m/s
2. The acceleration is -1.4 m/s²
3. The final velocity is zero
We need to find how long it takes the car to stop
We can find the time by using the rule
→ v = u + a t
where v is the final velocity, u is the initial velocity, a is the
acceleration and t is the time
→ v = 0 m/s , u = 19 m/s , a = -1.4 m/s²
Substitute these values in the rule
→ 0 = 19 + (-1.4) t
→ 0 = 19 - 1.4 t
Add 1.4 t to both sides
→ 1.4 t = 19
Divide both sides by 1.4
→ t = 13.57 ≅ 14 seconds
It takes the car 14 seconds to stop
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Answer:
563.64 m
Explanation:
Given that as per the question
x = 5 cm = 0.05 m
D = 4.2 × 107 m
d = smallest aperture size
As per the situation the solution of the smallest aperture telescope that she can get away with is below :-
We will use Rayleigh's diffraction limit which is
The equation will be
![d\frac{0.05}{4.2\times 10^7} = 1.22[550\times 10^{-9}]](https://tex.z-dn.net/?f=d%5Cfrac%7B0.05%7D%7B4.2%5Ctimes%2010%5E7%7D%20%3D%201.22%5B550%5Ctimes%2010%5E%7B-9%7D%5D)
d = 563.64 m
So, the answer is d = 563.64 m
The basic relationship between the frequency of a wave and its period is
where f is the frequency and T the period of vibration.
In our problem, the frequency is
so, by re-arranging the previous formula, we can find the period of the wave:
Answer:
Explanation:
Let the velocity after the 4 gram pencil strikes is v .
kinetic energy of the combination = 1/2 m v²
= .5 x ( 4 + 221 ) x 10⁻³ x v² = work done by friction
friction force acting on the combination = 225 x10⁻³x .325 x 9.8 = .7166 N
work done by friction
= .7166 x .119 = .085 J
.5 x 225 x 10⁻³ v² = .085
v² = .085 / .1125 = .7555
v = .8692 m = 86.92 cm /s
Velocity of combination after collision = 86.92 cm /s
Let velocity of pencil before collision be V
Applying law of conservation of momentum at the time of collision ,
4 x V = 225 x 86.92
V = 4889.25 cm / s
= 48.9 m /s .
No a wave with a high pitch has a very high frequency
