Respuesta :
Answer:
a. [tex]I=152\ N.s[/tex]
b. [tex]F=3040\ N[/tex]
c. [tex]m=309.8879\ kg[/tex]
Explanation:
Given:
- speed of the child and the car, [tex]v=8\ m.s^{-1}[/tex]
- time required to stop the child and the car, [tex]t=0.05\ s[/tex]
- mass of the child, [tex]m=19\ kg[/tex]
b. Now the force experienced by the child due to change in momentum with respect to time:
[tex]F=\frac{d}{dt}(p)[/tex]
where:
[tex]p=[/tex] momentum
[tex]\frac{d}{dt} =[/tex] rate of change with respect to time
as, [tex]p=m.v[/tex] here m is constant
[tex]F=m.\frac{dv}{dt}[/tex]
[tex]F=19\times\frac{(8-0)}{0.05}[/tex]
[tex]F=3040\ N[/tex]
c.
The equivalent mass of corresponding to the force due to change in momentum:
[tex]m=\frac{F}{g}[/tex]
[tex]m=\frac{3040}{9.81}[/tex]
[tex]m=309.8879\ kg[/tex]
a.
Now the impulse:
[tex]I=F.t[/tex]
[tex]I=3040\times 0.05[/tex]
[tex]I=152\ N.s[/tex]
Answer:
(a).The impulse needed to stop the child is 152 kg m/s.
(b). The average force on the child is 3040 N.
(c). The approximate mass of an object is 310.2 kg
Explanation:
Given that,
Speed of car = 8 m/s
Mass of child = 19 kg
Time = 0.050 s
(a). We need to calculate the impulse needed to stop the child
Using formula of impulse
[tex]J=m\Delta v[/tex]
[tex]J=m\times (v_{f}-v_{i})[/tex]
[tex]J=19\times(0-8)[/tex]
[tex]J=-152\ kgm/s[/tex]
Negative sign shows the net force is in negative direction.
The impulse needed to stop the child is 152 kg m/s.
(b). We need to calculate the average force on the child
Using formula of impulse
[tex]J=Ft[/tex]
[tex]F=\dfrac{J}{t}[/tex]
Put the value into the formula
[tex]F=\dfrac{-152}{0.05}[/tex]
[tex]F=−3040\ N[/tex]
Negative sign shows the opposite direction of the force
The average force on the child is 3040 N.
(c). We need to calculate the approximate mass of an object
Using formula of force
[tex]F=mg[/tex]
[tex]m=\dfrac{F}{g}[/tex]
Put the value into the formula
[tex]m=\dfrac{3040}{9.8}[/tex]
[tex]m=310.2\ kg[/tex]
The approximate mass of an object is 310.2 kg
Hence, (a).The impulse needed to stop the child is 152 kg m/s.
(b). The average force on the child is 3040 N.
(c). The approximate mass of an object is 310.2 kg
