Answer:
t₂ = 3.89 s
Explanation:
given,
speed of car = 23 m/s
speed of motorcycle = 23 m/s
after time of 4 s distance between them is equal to = 53 m
motorcycle accelerates at = 7 m/s
time taken to catch up with car = ?
let t₂ be the time in which motorcycle catches car.
distance traveled by car in t₂ s
d = 23 t₂ + 53
distance traveled by motorcycle
using equation of motion
now, equating both the distances
t₂ = 3.89 s
time taken by the motorcycle to catch the car is equal to 3.89 s
Answer:
work output is always less than work input - the ratio is less than 1.
Explanation:
This principle comes from the fact that a machine or system cannot produce more work than is supplied to it, because this would violate the energy conservation law (work is a type of mechanical energy).
In theoretical machines called "ideal machines" the input work is the same as the output work, but these machines are only theoretical because in real applications there is always some type of energy loss, either in heat produced by a machine or processes for its operation, for this reason the output work is always less than the input work.
Regarding the ratio work output to work input:
because work input WI is always greater than work output WO.
Answer:
False statement = There must be a non-zero net force acting on the object.
Explanation:
An object is moving at a constant speed along a straight line. If the speed is constant then its velocity must be constant. We know that the rate of change of velocity is called acceleration of the object i.e.
a = 0
⇒ The acceleration of the object is zero.
The product of force and acceleration gives the magnitude of force acting on the object i.e.
F = m a = 0
⇒ The net force acting on the object must be zero.
So, the option (a) is not true. This is because the force acting on the object is zero. First option contradicts the fact.