Explanation:
Initial time, t₁ = 2:30 pm
Final time, t₂ = 2:30:45
We need to find the motion of students in terms of time. Final time is 45 seconds more than the initial time.
Change in time,

Hence, this is the required solution.
Explanation:
It is given that,
Diameter of the semicircle, d = 45 m
Radius of the semicircle, r = 22.5 m
Speed of greyhound, v = 15 m/s
The greyhound is moving under the action of centripetal acceleration. Its formula is given by :



We know that, 


Hence, this is the required solution.
Answer:
So the acceleration of the child will be 
Explanation:
We have given angular speed of the child 
Radius r = 4.65 m
Angular acceleration 
We know that linear velocity is given by 
We know that radial acceleration is given by 
Tangential acceleration is given by

So total acceleration will be 
For this problem, we use our knowledge on trigonometric functions on a right triangle to be able to calculate for the x and y components of the walk. We do as follows:
sin 60 = ax / 9.4
ax = 8.14
cos 60 = ay / 9.4
ay = 4.7