Answer:
c
Explanation:
Hello!
To solve this problem we need to know the velocity and position of the train as a fucntion of time and acceleration. Since the train started from rest, these are the formulas:
v = at
x = (1/2)a*t^2
From the first equation we can know the time as a division between the velocity and the acceleration:
t = (v/a)
Replacing this value in the second equation we get:
x = (1/2)*a*(v/a)^2 = v^2/(2*a)
Solving for a:
a = (1/2)*(v^2/x)
Now, we know that when x=5.6km =5600 m, the velocity of the train is v =42 m/s
Therefore:
a = (1/2)*(42^2/5600) m/s^2 = 0.1575 m/s^2
So, the answer is c, the acceleration of the train during the first 5.6 km is colse to 0.16m/S^2
I would saw B. I choose B because translational motion is an object that shifts between one place to another.
Answer:
A. The ball has a negative acceleration on the way up and a positive acceleration on the way down.
Explanation:
- When a ball is thrown up vertically then the acceleration due to gravity always acts in a direction towards the center of the earth. So here when an object is thrown vertically upwards then the acceleration due to gravity acting in a downward direction which is opposite to the direction of motion of the object hence taken as negative with respect to the displacement.
- When the ball reaches at the top height its speed becomes zero and then it returns back towards the earth. While coming down the direction of the object's displacement is same as the direction of acceleration due to gravity.