read these expressions with break 10 maths them to the meanings break a lock does it mean a bit of bad luck to do or say something to start the conservation with someone who is being very quiet to remove one cell completely and finally from a situation to say the same thing over and over again used for wishing someone good luck especially before a performance used when the machine of vehicle stops workingread this
Add an Answer
More Questions From This User See All
Answers & Comments
Answer:
Explanation:
Question 1 )
Given : -
mass = 20 kg
initial velocity (u) = 5 m/sec
final velocity (v) = 2 m/sec
time (t)= 1sec
Solution : -
so , from first equation of motion
v= u+ at
or, a= ( v- u) / t
a= ( 2 ms-¹ - 5 ms-¹) / 15
a= - 3 ms-²
therefore, from third equation of motion
v²- u²= 2as
= ( 2ms -1 )² - ( 5ms-¹) ²
= 2× (-3ms-²) ×5
= -21 m²s² = -6ms-²× 5
= s = 7/2 metre
therefore, we know ,
workdone= f × s
and , F = m× a
so, work = m× a× s
= 20 kg × ( -3ms-²) × 7/2m
= - 210 joules.
Hence the answer is - 210
Question ( 2 )
Given : -
v = 5m/s
K.E = 25 J
Solution : -
K.E = 1/2 mv^2
25 = 1/2 m (5)^2
25 x 2 = 25m
m = 2 kg
Now if the velocity becomes 3 times then the velocity is 3 x 5 = 15m/S
Now new K.E = 1/2 x 2 x 15^2
= 225 J
Answer is 225 j