Question

what is the force produced on a body of 30kg mass when a body moving with the velocity of 26km/hr is acceleted to gain the velocity of 54 km/hr in 4 sec​

Answer 1

F = 58.35 [N]

Step-by-step explanation:

To solve this problem we must use Newton's second law, which tells us that force is equal to the product of mass by acceleration. But first we must use the following equation of kinematics.

We have to convert speeds from kilometers per hour to meters per second

`(26km)/(hr)*(1000m)/(1km)*(1hr)/(3600s)=(7.22m)/(s) \\(54km)/(hr)*(1000m)/(1km)*(1hr)/(3600s)=15(m)/(s)`

`v_(f)=v_(o)+(a*t) \\`

where:

Vf = final velocity = 15 [m/s]

Vi = initial velocity = 7.22 [m/s]

a = acceleration [m/s^2]

t = time = 4 [s]

Note: the positive sign of the above equation is because the car increases its speed

15 = 7.22 + (a*4)

a = 1.945 [m/s^2]

Now we can use the Newton's second law:

F = m*a

F = 30*1.945

F = 58.35 [N]