Answer:
Wolves are a keystone species because they are so important to the ecosystem that their removal causes a catastrophic disequilibrium.
Explanation:
Wolves are the predators available in the environment but they exist in relatively less number while comparing it with another species of animals. Wolves influence their pray which are influenced by plants. Thus, They are so important to the ecosystem that their removal causes a catastrophic disequilibrium.
1. e) None of the above is necessarily true.
2.d) Without knowing the mass of the boat and the sack, we cannot tell.
Answer:
Explanation:
Let the extension in the spring be x .
restoring force = weight of block
kx = mg
x = 
= 23.84 cm
b )
When the elevator is going upwards
Restoring force = mg + ma
k x₁ = 10.9 ( 9.8 + 1.89 )
x₁ = 28.44 cm
( y coordinate will be - ( 28.44 - 23.84 ) = - 4.6 cm )
c ) When the cable snaps , both elevator and block undergo free fall . In this case apparent g = 0
Since the spring is stretched by 28.44 cm , a restoring force continues to act on the block which is equal to
.2844 x 448
= 127.41 N
So a net acceleration a will act on the block
a = 127.41 / 10.9
= 11.68 m / s²
The block will undergo SHM with amplitude equal to 28.44 cm .
X ray is one of the electromagnetic waves.
As per Clark Maxwell's electromagnetic theory, all the electromagnetic waves move with the velocity of light i.e c= 3×10^8 m/s
In case of electromagnetic waves,the electric field and magnetic field are perpendicular to each other as well as perpendicular to the direction of propagation.The electromagnetic waves exhibit the property of polarisation. Hence they are transverse in nature.
Hence the best statements about X- ray will be-
1- X -rays are electromagnetic waves
2-X-rays are transverse transverse waves
3- X- rays travel at the speed of light.
Answer:All planets move in elliptical orbits, with the sun at one focus. This is one of Kepler's laws. The elliptical shape of the orbit is a result of the inverse square force of gravity. The eccentricity of the ellipse is greatly exaggerated here.
so it is true
Explanation:
