To find the velocity of the ball, we need to use the concept of momentum. Momentum is the product of an object's mass and its velocity. In this case, we are given that the momentum of the boy is equal to the momentum of the ball.
The momentum of an object can be calculated using the formula: momentum = mass × velocity.
We know the mass of the ball is 3.5 kg, but we don't have the velocity of the ball yet. Let's represent the velocity of the ball as 'v'.
Since the momentum of the boy is equal to the momentum of the ball, we can write an equation: momentum of boy = momentum of ball.
The momentum of the boy is not given in the question, so let's assume it as 'M'.
Using the formula for momentum, we can write: M = mass of boy × velocity of boy.
Now, let's equate the momentum of the boy to the momentum of the ball: M = 3.5 kg × v.
To find the velocity of the ball, we need to solve this equation for 'v'.
Dividing both sides of the equation by 3.5 kg, we get: v = M / 3.5 kg.
So, the velocity of the ball is equal to the momentum of the boy divided by 3.5 kg.
Please note that we can't find the exact velocity of the ball without knowing the momentum of the boy. However, if we are given the momentum of the boy, we can use the equation v = M / 3.5 kg to find the velocity of the ball.