Collaboration in science is important because if only one scientist does an experiment, and gets a result, he/she could have messed. So this is where collaboration comes in. A few other scientists could try the experiment, and if they get the same answers, the result may be proven correct.
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Answer:
t₁ > t₂
Explanation:
A coin is dropped in a lift. It takes time t₁ to reach the floor when lift is stationary. It takes time t₂ when lift is moving up with constant acceleration. Then t₁ > t₂, t₁ = t₂, t₁ >> t₂ , t₂ > t₁
Solution:
Newton's law of motion is given by:
s = ut + (1/2)gt²;
where s is the the distance covered, u is initial velocity, g is the acceleration due to gravity and t is the time taken.
u = 0 m/s, t₁ is the time to reach ground when the light is stationary and t₂ is the time to reach ground when the lift is moving with a constant acceleration a.
hence:
When stationary:

Hence t₂ < t₁, this means that t₁ > t₂.
Answer:
So time taken by block to travel 0.5 m from rest will be 0.4853 sec
Explanation:
We have given mass of the block m = 6.7 kg
angle of inclination 
Distance traveled s = 0.5 m
Initial velocity u = 0 m/sec
Acceleration of the block 
From second equation of motion we know that 
So 

t = 0.4853 sec
So time taken by block to travel 0.5 m from rest will be 0.4853 sec