As long as it sits on the shelf, its potential energy
relative to the floor is . . .
Potential energy = (mass) x (gravity) x (height) =
(3 kg) x (9.8 m/s²) x (0.8m) = <u>23.52 joules</u> .
If it falls from the shelf and lands on the floor, then it has exactly that
same amount of energy when it hits the floor, only now the 23.52 joules
has changed to kinetic energy.
Kinetic energy = (1/2) x (mass) x (speed)²
23.52 joules = (1/2) x (3 kg) x (speed)²
Divide each side by 1.5 kg : 23.52 m²/s² = speed²
Take the square root of each side: speed = √(23.52 m²/s²) = <em>4.85 m/s </em> (rounded)
Answer:
Naturally occurring radio waves are made by lightning or by astronomical objects. Artificially generated radio waves are used for fixed and mobile radio communication, broadcasting, radar and other navigation systems, communications satellites, computer networks and innumerable other applications.
Explanation:
Answer:
(a) Time t = 16.46 sec
(b) Time t =13.466 sec
(c) Deceleration = 
Explanation:
(a) As the train starts from rest its initial velocity u = 0 m/sec
Acceleration 
Final speed v = 80 km/hr
From first equation of motion v =u+at
So 
(b) Now initial speed u = 22.22 m/sec
As finally train comes to rest so final speed v=0 m/sec
Deceleration 
So 
(c) We have given that initial velocity = 80 km/hr = 22.22 m/sec
Final velocity v = 0 m/sec
Time t = 8.30 sec
So acceleration is given by
As acceleration is negative so it is a deceleration
Answer:
D. 100 cm
Explanation:
The speed of a wave is the wavelength times the frequency.
v = λf
Wave A and B have the same speed, so:
λf = λf
(50 cm) (7000 Hz) = λ (3500 Hz)
λ = 100 cm
Explanation:
A compound is a pure substance composed of two or more different atoms chemically bonded to one another. A compound can be destroyed by chemical means. It might be broken down into simpler compounds, into its elements or a combination of the two.
