Most organisms either directly or indirectly use energy from the sun to survive, but not all of them. Plants and some microbes use the energy from the sun to perform photosynthesis.
I think the hydra lacks the specialized cells for touch and chemical detection. On the other hand earthworms have touch, light, vibration and chemical receptors along the entire body surface. Both of them are invertebrates (those animals without a backbone), they include insects, worms, jelly fish, spiders among other animals.
I think it is from the Paleozoic era
Hope this helps
Force required = F = ?
mass of the car = m = 1200 kg
initial velocity of the car = Vi = 10 m/sec
final velocity of the car = 0
time required to stop the car = t = 20 sec
Using Newton`s 2nd law of motion;
F = ma ………………………(1)
as a = Vf - Vi / t , put this value in equation (1)
F = m ( Vf - Vi /t ) ………………(2)
F = 1200 ( 0 - 10 /20) = - 600 N
here Negative sign shows that external force is acting in opposite direction of the motion to bring it to rest.
we can also calculate this force by using the relation
Rate of change of momentum = net force acting on the object …………(3)
m Vf - m Vi / t = net force acting on the object
m (Vf - Vi / t) = F
1200 ( 0 - 10 /20) = - 600 N = F
so, net force acting on the object =F = - 600 N
