Aparticle's trajectory is described by x =(1/2t3? 2t2)m and y =(1/2t2? 2t)m, where t is in s, what is the particle's speed at t=4.5s ?

As we know that it is given to us

now we know that rate of change in position is known as velocity

so here we will have

similarly

now we have t = 4.5 s

now the net speed is given as

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s