A ball spins on a 0.5m-long string with a speed of 3.8m/s. Calculate the acceleration of the ball.

v^2/R

or are you supposed to derive centripetal acceleration?

s = speed
w = angular velocity = s/r radians/s
V = velocity vector = Vx i + Vy j
Vx = s cos theta
Vy = s sin theta
theta = w t
V = s cos wt i + s sin w t j
A = dV/dt
A= -s w sin w t i + s w cos w t j
but w = s/r
A = -s^2/r sin wt i + s^2/r cos w t
|A| = s^2/r sqrt(sin^2+cos^2)
= s^2/r
if you look at the direction of the acceleration, it is toward the origin :)

To calculate the acceleration of the ball, you need to find out the centripetal acceleration. Centripetal acceleration is the acceleration experienced by an object moving in a circular path.

The formula for centripetal acceleration is given by:

a = v^2 / r

where:
a = centripetal acceleration
v = velocity of the ball
r = radius of the circular path

In this case, the velocity of the ball is 3.8 m/s and the radius of the circular path is 0.5 m.

Plugging these values into the formula, we have:

a = (3.8^2) / 0.5

a = 14.44 / 0.5

a = 28.88 m/s^2

Therefore, the acceleration of the ball is 28.88 m/s^2.