Atruck on a straight road starts from rest and accelerates at 1.4 m/s 2 until it reaches a speed of 22 m/s. then the truck travels for 22 s at constant speed until the brakes are applied, stopping the truck in a uniform manner in an additional 4.4 s. how long is the truck in motion?

42.11 sec

Explanation:

In first part : The truck start from the rest that is u = 0 m/sec

Acceleration is given as

It reaches to a velocity of 22 m/sec so v=22 m/sec

Now according to first law of motion

In second part : The truck maintain a constant speed for 22 sec

In third  part : The truck takes an additional 4.4 sec for stopping

So total time in which the truck is in motion =15.71+22+4.4=42.11 sec

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27

dang that balls went far