Answer: The correct answer is "Number of rope segments supporting the load".
Explanation:
Mechanical advantage: It is defined as the ratio of the force produced by a machine to the force applied on the machine. The ideal mechanical advantage of a machines is mechanical advantage in the absence of friction.
The ideal mechanical advantage of a pulley system is equal to the number of rope segments which is supporting the load. More the rope segments, It is more helpful to do the lifting the work.
It means that less force is needed for this task to complete.
Therefore, the correct option is (C).
Answer:
17.5
or
1.1 g/min
I know it's one of these, try getting a second opinion
f' = frequency observed by the police car after sound reflected from the vehicle and comes back to police car = 1250 Hz
f = frequency emitted by the police car = 1200 Hz
V = speed of sound = 340 m/s
v = speed of vehicle = ?
frequency observed by the police car is given as
f' = f (V + v)/(V - v)
inserting the values in the above equation
1250 = 1200 (340 + v)/(340 - v)
v = 6.9 m/s
Answer: coefficient of static friction
= 0.31
Explanation: Since they negotiate the curve without skidding, the frictional force (F1) equals the centripetal force (F2).
F1= uN
F2 = M*(v²/r)
M is the combined mass 450kg
V is the velocity 18m/s
r is the radius 106m
N is the normal reaction 4410N
u is the coefficient of static friction
Making u subject of the formula we have that,
u = {450*(18²/106)} /4410
=1375.47/4410
=0.31
NOTE: coefficient of friction is dimensionless. It as no Unit.
Answer:
(a) 
(b) 
(c) 
Explanation:
(a) According to Newton's second law, the acceleration of a body is directly proportional to the force exerted on it and inversely proportional to it's mass.

(b) According to Newton's third law, the force that the sled exerts on the girl is equal in magnitude but opposite in the direction of the force that the girl exerts on the sled:

(c) Using the kinematics equation:

For the girl, we have
and
. So:

For the sled, we have
. So:

When they meet, the final positions are the same. So, equaling (1) and (2) and solving for t:

Now, we solve (1) for 
