Answer:
60 km
Explanation:
For an object (or a person, such as in this case) moving at constant speed, the speed is equal to the ratio between the distance travelled and the time taken:

where
v is the speed
d is the distance
t is the time taken
In this case, we have:
v = 120 km/h is the speed
t = 30 min = 0.5 h is the time taken
Therefore, we can rearrange the equation to find the total distance travelled:

Answer:
the maximum angular speed (in radians per second) of a Blu-ray disc as it rotates is 57.6 m/s
Explanation:
Given information:
diameter of the disc, d = 11 cm, r = 5.5 cm = 0.055 m
angular speed ω = 10000 rev/min = (10000 rev/min)(2π rad/rev)(1/60 min/s)
= 1000π/3 rad/s
to calculate the maximum angular speed we can use the following formula
ω = v/r
v = ωr
= (1000π/3)(0.055)
= 57.6 m/s
Answer:
E. all of these
Explanation:
The designation of a point in space all the points that necessary
- reference point
- a direction
- fundamental units
- a direction
- motion
all are necessary to designate a point in space. Hence option E is correct.
For example in simple harmonic motion we need to specify all the above factors of the object in order to designate the position of the object.
Answer:
P = 96 J
Explanation:
Given that,
Weight of the book, W = mg = 8 N
It is placed at a height of 12 m
We need to find the potential energy of the book. The potential energy of an object is given by the formula as follows :
E = mgh
mg = Weight

So, the potential energy of the book is 96 J.
Answer:
a)
b)
Explanation:
a)
The width of the central bright in this diffraction pattern is given by:
when m is a natural number.
here:
- m is 1 (to find the central bright fringe)
- D is the distance from the slit to the screen
- a is the slit wide
- λ is the wavelength
So we have:
b)
Now, if we do m=2 we can find the distance to the second minima.

Now we need to subtract these distance, to get the width of the first bright fringe :
I hope it heps you!