3. An particle moving in a straight line has an initial speed of 300m/s. It unde

Question

3. An particle moving in a straight line has an initial speed of 300m/s. It undergoes acceleration of 85m/s. (a) How long will i take to reach a far will it have traveled in this time? t take to reach a speed of 600 ms7 ) How 4 + 4. A small mailbag is released from the top of a building. After 2.5s, (a) what is the speed of the mailbag, and (b) how far is it below the top of the building? 5. A student throws a set of keys vertically upward to his fratermity brother, who is in a window 8.00m above. The brother catches the key 2 s later. (a) With what initial velocity are the key thrown? (b) What is the velocity of the keys just before they are caught?

Explanation / Answer

3.

Using 1st equation of motion

t= (v-u)/a= (600-300)/85= 3.529 second . (Ans)

Using 3rd equation of motion

V^2= u^2+ 2ad

600^2= 300^2+2* 85*d

d= 1588.235 m (ans)

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2.

Velocity at given instant of time

v= gt= 9.8*2.5= 24.5 m/s .(ans)

Distance from the top of the building

d= 0.5gt^2= 0.5* 9.8*2.5^2

= 30.625 m (ans)

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3.

Using 2nd equation of motion

S= ut-0.5gt^2

8= u* 2-4.9*2^2

u= 13.8 m/s. (Ans)

Velocity during catch

V= u-gt

=13.8-9.8*2

= 5.8 m/s directed downward

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Comment in case any doubt.. good luck

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