The correct answer to the question is: A) miles/hour and B) metre/ second.
EXPLANATION:
Before answering this question, first we have to understand speed.
The speed of a body is defined as the rate of distance travelled or the distance travelled by a body per unit time.
Hence, it is a derived quantity which is obtained from distance and time.
The unit of distance can be metre, miles, and the unit of time can be second, minutes or hour.
As speed is the distance covered per unit time, the perfect units will be miles/hour and metre/second.
Hence, the correct options are first and second.
Answer:
One would need to know how far apart the towns are:
T = SA / 40 time it takes for first cyclist to travel S1
T = SB / 60 time it takes for cyclist B to travel distance S2
SA + SB = S the distance between the towns
SB = 60 / 40 SA = 1.5 SA
SA + 1.5 SA = S
S = 2.5 SA where cyclist travels distance SA
The time will depend on the separation of the towns.
Here the block has two work done on it
1. Work done by gravity
2. Work done by friction force
So here it start from height "h" and then again raise to height hA after compressing the spring
So work done by the gravity is given as
Now work done by the friction force is to be calculated by finding total path length because friction force is a non conservative force and its work depends on total path
Total work done on it
So answer will be
None of these
