When Adam applies a ‘pull’ force on the pulley, there is an output force that the pulley lets out, directly pulling the object with it. We cannot always pull up objects with our bear hands, no matter how much force we apply. Which is why pulleys allow us to apply the force and pulleys do the work of pulling the objects for us, since work and force come hand in hand.
Answer:
The right answer is:
(a) 63.83 kg
(b) 0.725 m/s
Explanation:
The given query seems to be incomplete. Below is the attachment of the full question is attached.
The given values are:
T = 3 sec
k = 280 N/m
(a)
The mass of the string will be:
⇒ 
or,
⇒ 
On substituting the values, we get
⇒ 
⇒ 
⇒ 
(b)
The speed of the string will be:
⇒ 
then,
⇒ 
On substituting the values, we get
⇒ 
⇒ 
⇒ 
⇒ 
The answer to this is A. this is because, refraction with a light or sound wave changing its direction involve propagation,(in which propagation is the change in direction of a light or sound wave)
Answer:
B, it includes a control group and an experimental group.