Given mass of the object, m = 50kg ;
Initial velocity, u = 4m/s ;
Final velocity, v = 8m/s ;
Time, t = 8s ;
Initial momentum, p1= mu= 50×4=200kgms ^-1 ;
Final momentum, p2= mv=60×8= 400kgms^-1 ;
Force = momentum change / time = p2 - p1 / t ;
putting the values , we get
Force = 400-200/8 =200/8= 25 N
Hence, the magnitude of the force exerted by the object is 25 N.... hope it'll help u.. :)

Calculation of Initial and Final Momentum:

The momentum of an object is the product of its mass and velocity. Therefore, the initial momentum of the object can be calculated as follows:

Initial Momentum = Mass x Initial Velocity

Initial Momentum = 50kg x 4m/s

Initial Momentum = 200kgm/s

Similarly, the final momentum of the object can be calculated as follows:

Final Momentum = Mass x Final Velocity

Final Momentum = 50kg x 8m/s

Final Momentum = 400kgm/s

Therefore, the initial momentum of the object is 200kgm/s, and the final momentum of the object is 400kgm/s.

Calculation of Magnitude of Force:

The acceleration of the object can be calculated using the formula:

Acceleration = (Final Velocity - Initial Velocity) / Time Taken

Acceleration = (8m/s - 4m/s) / 8s

Acceleration = 0.5m/s²

Now, the force exerted on the object can be calculated using Newton's second law of motion, which states that the force acting on an object is equal to the product of its mass and acceleration. Therefore, the force exerted on the object can be calculated as follows:

Force = Mass x Acceleration

Force = 50kg x 0.5m/s²

Force = 25N

Therefore, the magnitude of the force exerted on the object is 25N.

Explanation:

The question requires us to calculate the initial and final momentum of an object and the magnitude of the force exerted on the object. To calculate the initial and final momentum of the object, we need to use the formula for momentum, which is the product of mass and velocity. Once we have calculated the initial and final momentum, we can use Newton's second law of motion to calculate the magnitude of the force exerted on the object. The second law states that force is equal to mass times acceleration. We can calculate the acceleration of the object using the formula for acceleration, which is the change in velocity divided by the time taken. Once we have calculated the acceleration, we can use it to calculate the force exerted on the object.