please help me!!! 1)A car whose initial speed is 30 m/s slows uniformly to 10 m/

Question

please help me!!!

1)A car whose initial speed is 30 m/s slows uniformly to 10 m/s in 5 sec. Determine the distance it travels during this time???

2)A bus moving at 20 m/s slows at a rate of 4 m/s2.  It stops.  How far does it travel while braking?

3)While ambling along at 0.5 m/s, a bear spies some honey and accelerates at a rate of 2 m/s2.  If the honey is 10 m distant when she first begins to accelerate, what speed will she have upon reaching her prize?

4) A marble has an initial velocity of 8 m/s.  It is accelerated at a rate of 10 m/s2 along a tabletop surface for 5.5 s.    
            a.  Calculate the final velocity of the marble.

b.  Calculate its displacement during this time interval?

Explanation / Answer

1.) a = (v-u)/t = -4m/s^2

s = ut-0.5at^2 = 30*5 -0.5*4*25 =100 m

2.)v^2 -u^2 = 2as =. s = (20*20-0)/2*4 =50m

3.) v^2 = u^2 + 2as = 0.5*0.5 + 2*2*10 = 40.25 => v = 6.34428877

4.) v = u +at = 8+10*5.5 = 63m/s

s =( v^2-u^2)/2a = (63*63 - 8*8)/20 = 195.25m

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