Question

A moving body of mass 400N posses 500J of Kinetic Energy.Calculate it's velocity take g = 10ms^-2
@perl
@rvc

Answer 1

What are things are given?
Make a note of the data

Answer 2

Mass=400N
K.E=500J
g = 10ms^-2
v = ?

Answer 3

correct :)
Now what is the formula of KE ?

Answer 4

K.E = mv^2/2

Answer 5

correct :)
we need velocity so keep the v term on the RHS and the rest on the LHS

Answer 6

But,Mass gievn 400N I need to convert it to kg

Answer 7

yeah
do you know the conversion?

Answer 8

No :(

Answer 9

oh
well
what is the relation between newton and kg?

Answer 10

iDK
Newtonis unit of force while kg is unit of mass :/

Answer 11

mg

Answer 12

\[ma=mv ^{2}/2\]

Answer 13

yeah
here for a we put g

Answer 14

mass gets cut off... hence dont worry abt mass

Answer 15

nope
wait we have KE=500J
we need to convert mass

Answer 16

oh ya... sry.. i messed up..

Answer 17

I'm confused :(

Answer 18

well u just need to convert N to kg and rest is easy
divide the mass by 10

Answer 19

1N = how many kg? :/

Answer 20

@rvc

Answer 21

sorry
os is lagging for me

Answer 22

1N=0.10kg

Answer 23

just divide the mass by 10

Answer 24

How?
How 10?

Answer 25

oops

Answer 26

multiply

Answer 27

@IrishBoy123 please confirm

Answer 28

im confused :/

Answer 29

i just want to confirm about the conversion
@Callisto

Answer 30

HELP :(

Answer 31

@butterflydreamer

Answer 32

@mathmate

Answer 33

@Michele_Laino will surely help :)

Answer 34

hint:
if you use the Newton as unit of measure, then 400N is a weight, not a mss

Answer 35

oop.. ...not a mass...

Answer 36

so its F=mg
therefore
m= \(\frac{f}{g}\)

Answer 37

that's right! @rvc
So, m=400/9.81=...? @AaronAndyson

Answer 38

or:
m=400/10=...?

Answer 39

well it is given that g=10m/s^2

Answer 40

haha so you need to divide by 10

Answer 41

40?
But,I still can't understand HOW?

Answer 42

what is the formula for force???

Answer 43

F = MG

Answer 44

ok! our particle has a mass of 40 Kg
so its sped is given by the subsequent formula:
\[\Large v = \sqrt {\frac{{2KE}}{m}} = ...?\]
where KE is its kinetic energy

Answer 45

correct

Answer 46

I think he was confused with the conversion part only
well rest is easy
just put those values and find out the answer

Answer 47

\[\Large v = \sqrt {\frac{{2 \times KE}}{m}} = \sqrt {\frac{{2 \times 500}}{{40}}} = ...?\]

Answer 48

what is v? @AaronAndyson

Answer 49

All the best!!
@AaronAndyson

Answer 50

5?

Answer 51

that's right!
v= 5 meters/second

Answer 52

Yet,I have no idea HOW

Answer 53

keep in mind that the kinetic energy KE, of a particle, whose mass is m, and whose speed is v, is given by the subsequent formula:
\[\Large KE = \frac{1}{2} \times m \times {v^2}\]

Answer 54

since the weight of your particle, is P=400 Newton, then its mass is:
\[\Large m = \frac{P}{g} \cong \frac{{400}}{{10}} = 40\;{\text{Kg}}\]

Answer 55

DUH
Thanks
LOL
XD

Answer 56

thanks!