A motor car is moving with a velocity of 90 km/h and it takes 4s to stop after the brakes are applied calculate the force exerted by the break on the motor car if the mass along with the passenger is 1000kg
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Answered by
14
Hey !!
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There is retardation so force can't be positive if you have to show itpositive you must write down it is retardation and force is acting in opposite direction of motion
remember it next time
thanks ji
thanks ji
why ji i am just 14
Answered by
16
we know thatF=ma
we already know m=1000kg
we need to find a
appliying 1st equation of motion
v=u+at
v=0 (the car stops)
u=90km/h
(90×5)÷18 (to change from km/hr to m/s
we multiply velocity or speed
by 5/18)
450÷18
25m/s
we know t=4sec
putting the values
0=25+a(4)
-25=4a
-25÷4=a
-6.25m/s^2=a
or
a=-6.25m/s^2
substituting values of 'a' and 'm' in F=ma
F=1000×(-6.25)
-6250Kgm/s^2
-6250N
we already know m=1000kg
we need to find a
appliying 1st equation of motion
v=u+at
v=0 (the car stops)
u=90km/h
(90×5)÷18 (to change from km/hr to m/s
we multiply velocity or speed
by 5/18)
450÷18
25m/s
we know t=4sec
putting the values
0=25+a(4)
-25=4a
-25÷4=a
-6.25m/s^2=a
or
a=-6.25m/s^2
substituting values of 'a' and 'm' in F=ma
F=1000×(-6.25)
-6250Kgm/s^2
-6250N
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