physics

Asked by anilchavan8103 | 19th Aug, 2020, 01:10: PM

Expert Answer:

1) u = 2 m/s, a = 4 m/s2, t = 3 s
 v = u+ at 
v = 2 + 4 x 3 = 14 m/s 
 
2) v = 20 m/s
t =2 s, a =5 m/s2 
thus, 
u = v - at 
u = 20 - 5 x 2 =  20-10 = 10 m/s 
 
3) s = ut  +1/2 at2 
s = 5 x3 + (1/2) 12 x 32 = 15 +54 =69 m 
 
4)  
s space equals space 92 space m
t space equals space 4 space s comma space u space equals space 7 space m divided by s comma space a space equals ?
s space equals space u t plus space 1 half a t squared space
92 space equals space 7 cross times 4 space plus space 1 half a space open parentheses 4 close parentheses squared space
92 space equals space 28 space plus space fraction numerator 16 a over denominator 2 end fraction
therefore 92 space equals space 28 space plus space 8 space a space
92 minus 28 space equals space 8 a space
T h u s comma space
8 a space equals space 64
therefore space a space equals space 8 space m divided by s squared 
 
5) u =4 m/s, a = 3m/s2 , s  =? , v2 = 8 (m/s)2
u space equals 4 space m divided by s comma space a space equals space 3 m divided by s squared space comma space s space space equals ? space comma space v space equals space 8 space m divided by s
v to the power of 2 space end exponent space equals space u squared plus 2 a s
64 space equals open parentheses space 4 close parentheses squared space plus space 2 space cross times space 3 space cross times s
therefore space 64 space equals space 16 space plus space 6 s space
therefore space 64 minus 16 space equals space 6 s
therefore s space space equals space space 48 over 6 space equals space 8 space m space space 
 
6)
space u space space equals ? comma space a space equals 5 space m divided by s squared comma space s space space equals 8.4 space m space comma space v equals space 10 space m divided by s space space
v to the power of 2 space end exponent space equals space u squared plus 2 a s
100 space equals open parentheses space u close parentheses squared space plus space 2 space cross times space 5 space cross times 8.4
therefore 100 minus 84 space equals space u squared
therefore space 16 space equals space u squared
therefore u space space equals space space 4 space m divided by s space

Answered by Shiwani Sawant | 19th Aug, 2020, 04:53: PM