72km/hr = 72000m/3600seconds(we convert km/hr to m/s
= 20m/s
Velocity= 20m/s
In 4seconds,distance covered=20x4= 80m
Therefore,an accident occurs because in 4seconds, the car would have moved past 20m

6 0

2 years ago

A car is pushed with a force of 450 N for 19.4 seconds. What impulse was applied to the car?

harina [27]

Answer:

impulse = 8820 kg· $\frac{m}{s}$ or 8820 N·s

Explanation:

Impulse J is equal to the average force $F_{av}$ multiplied by the elapsed time Δt or in equation form, J = $F_{av}$ Δt

As long as your force of 450 N is constant then that value is your average force $F_{av}$ and your elapsed time is 19.4 seconds.

Multiply these values.

You will get an impulse of 8820 kg· $\frac{m}{s}$ or 8820 N·s.

6 0

2 years ago

I need help with these questions

Feliz [49]

7. PE=0.5×700n/m×0.9m^2
0.9^2=0.81m
0.5×700×0.81= 283.5J

8. 2000=0.5×(x)×1.5m^2
1.5^2= 0.25
0.25×0.5=0.125
2000=0.125 (x)
2000/0.125=x
x=16000 n/m

9. 4000=0.5 (375 n/m)×(x)^2
0.5×187.5 (x)
4000/187.5=21.3333333333

6 0

3 years ago