A ball of mass 2kg travelling in a straight line at 4ms^-1 is acted on by a force of 3N acting in the direction of motion for 5 seconds. What is the speed of the ball after 5 seconds?
To determine the speed of the ball after 5 seconds, you first need to find the acceleration experienced by the ball. The acceleration can be calculated using Newton's second law of motion, which states that the force acting on an object is equal to the mass of the object multiplied by its acceleration:
Force = mass × acceleration
In this case, the given force acting on the ball is 3N, and the mass of the ball is 2kg. Rearranging the equation to solve for acceleration:
Acceleration = Force / Mass
Acceleration = 3N / 2kg
Now, plug in the values to find the acceleration:
Acceleration = 3N / 2kg
Acceleration = 1.5 m/s²
Next, use the equation for constant acceleration to calculate the final velocity of the ball:
final velocity = initial velocity + (acceleration × time)
The initial velocity of the ball is given as 4 m/s, the acceleration is calculated as 1.5 m/s², and the time is 5 seconds. Plug in the values to find the final velocity:
final velocity = 4 m/s + (1.5 m/s² × 5 s)
final velocity = 4 m/s + 7.5 m/s
final velocity = 11.5 m/s
Therefore, the speed of the ball after 5 seconds is 11.5 m/s.