ACTIVITY!
1. A skateboarder accelerates uniformly from rest at 3 m/s² for 5 seconds.
How far has the skateboarder traveled?
2. An object is moving with an initial velocity of 6 m/s and accelerates at 2 m/s².
What is its final velocity if it has travelled a distance of 75 m?
3. With an initial velocity of 20 m/s, a car accelerated at 8 m/s² for 10 seconds.
What is the position of the car at the end of the 10 seconds?



Answer :

Let's solve each activity one by one: ### Activity 1: - **Given:** - Acceleration, `a` = 3 m/s² - Time, `t` = 5 seconds - Initial velocity, `u` = 0 m/s We can use the kinematic equation for uniformly accelerated motion to find the distance `s` traveled: \[ s = ut + \frac{1}{2}at^2 \] Let's plug in the values: \[ s = (0 \, m/s \cdot 5 \, s) + \frac{1}{2} \cdot (3 \, m/s² \cdot (5 \, s)^2) \] \[ s = 0 + \frac{1}{2} \cdot 3 \cdot 25 \] \[ s = \frac{3}{2} \cdot 25 \] \[ s = 1.5 \cdot 25 \] \[ s = 37.5 \, m \] The skateboarder has traveled 37.5 meters. ### Activity 2: - **Given:** - Initial velocity, `u` = 6 m/s - Acceleration, `a` = 2 m/s² - Distance, `s` = 75 m We can use another kinematic equation to find the final velocity `v`: \[ v^2 = u^2 + 2as \] Substitute the given values: \[ v^2 = (6 \, m/s)^2 + 2 \cdot (2 \, m/s² \cdot 75 \, m) \] \[ v^2 = 36 + 2 \cdot 150 \] \[ v^2 = 36 + 300 \] \[ v^2 = 336 \] Take the square root of both sides to find `v`: \[ v = \sqrt{336} \] \[ v \approx 18.33 \, m/s \] The final velocity of the object is approximately 18.33 m/s. ### Activity 3: - **Given:** - Initial velocity, `u` = 20 m/s - Acceleration, `a` = 8 m/s² - Time, `t` = 10 seconds Using the same kinematic equation as in Activity 1 to find position `s`: \[ s = ut + \frac{1}{2}at^2 \] Substitute the values: \[ s = (20 \, m/s \cdot 10 \, s) + \frac{1}{2} \cdot (8 \, m/s² \cdot (10 \, s)^2) \] \[ s = 200 + \frac{1}{2} \cdot 8 \cdot 100 \] \[ s = 200 + 4 \cdot 100 \] \[ s = 200 + 400 \] \[ s = 600 \, m \] The position of the car at the end of the 10 seconds is 600 meters from the starting point.