Answer:
The correct answer will be "1477.84 N".
Explanation:
Given that,
Mass,
m = 1.6 mg
or,
= 1600 kg
Initial velocity,
u = 72 km/h
= [tex]72\times \frac{5}{18} \ m/s[/tex]
= [tex]20 \ m/s[/tex]
Final velocity,
v = 18 km/h
= [tex]18\times \frac{5}{18}[/tex]
= [tex]5 \ m/s[/tex]
Covered distance,
s = 250 m
By using the below relation, we get
⇒ [tex]v^2=u^2+2as[/tex]
On putting the values, we get
⇒ [tex](5)^2=(20)^2+2\times a\times 250[/tex]
⇒ [tex]a=-0.75 \ m/s^2[/tex] (shows the deceleration)
Slope will be given as 1 in 25, then
⇒ [tex]Sin \theta=\frac{1}{25}[/tex]
[tex]\theta=2.3^{\circ}[/tex]
hence,
As we know,
⇒ [tex]\Sigma F=ma[/tex]
or,
⇒ [tex]Braking \ force+350-mgSin\theta=ma[/tex]
⇒ [tex]Braking \ force=ma+mgSin\theta-350[/tex]
On substituting all the values, we get
⇒ [tex]=1600(0.75+1600\times 9.81 Sin(2.3^{\circ})-350[/tex]
⇒ [tex]=1477.84 \ N[/tex]
