Answer:
Frictional force always acts parallel to two planes in contact with each other and in a direction opposite to that of relative motion of the two bodies. 2. Frictional forces are caused due to intermolecular interactions between the bodies. Frictional force is more for rough surface and less for smooth surfaces.
v = speed of car = 90 km/h
u = speed of truck = 50 km/h
d = initial separation distance = 100 m = 0.1 km
They meet at time t such that
vt = d + ut
t(v - u) = d
t = d/(v - u) = (0.1 km) / [(90 - 50) km/h] = 0.0025 hours
I think the correct answer would be the rays of light focus behind the retina. It is a condition called farsightedness or hyperopia. Due to his, objects that are close to the eyes seems to be blurry and as it worsens everything would become blurry to the eye.
Writing the acceleration as a function of time:
a(t) = 1 + 3√t
Integrating acceleration, we obtain velocity:
v(t) = t + 2(t)^(3/2) + c;
object at rest so velocity at t = 0 is 0 so c = 0.
v(t) = t + 2(t)^(3/2)
Integrating velocity to obtain an equation for displacement:
d(t) = t²/2 + 4/5 t^(5/2) + c
Applying limits from t = 0 to t = 9
d = 9²/2 + 4/5 9^(5/2)
d = 234.9 m
It is the energy an object has because of its motion.