Physics Q (1 Viewer)

[Xyzpt]

Not sure what the answer is to iv.


Please help. Thanks!

 

[jimmysmith560]

Would the following help?

 

[Xyzpt]

Sorry. I'm still not sure.

 

[liamkk112]

Not sure what the answer is to iv.


Please help. Thanks!

so first of all, we know the maximum acceleration possible for your car is 8.3 km/h = 0.002 km/s, as is given in the question. firstly we should work out how long it takes for the car to accelerate to 60km/h = 0.016 km/s and travel 5km. from v= u+at, we see it will take t = 8s for the car to reach 60km/h from rest. we can then use s = ut + 1/2at^2 to determine how much the car has already travelled while it was accelerating, which gives s = 0.064km. so now we need to work out how long it takes for the car to travel the remaining 4.936km, which by s = ut (as a is now 0) gives t = 308.5, so in total it takes t = 316.5s for the car to accelerate from rest to 60km/h and travel 5km from its starting point. similar process for the 50km/h, then just take the difference of the times. lmk if u want me to clarify anything

 

[liamkk112]

so first of all, we know the maximum acceleration possible for your car is 8.3 km/h = 0.002 km/s, as is given in the question. firstly we should work out how long it takes for the car to accelerate to 60km/h = 0.016 km/s and travel 5km. from v= u+at, we see it will take t = 8s for the car to reach 60km/h from rest. we can then use s = ut + 1/2at^2 to determine how much the car has already travelled while it was accelerating, which gives s = 0.064km. so now we need to work out how long it takes for the car to travel the remaining 4.936km, which by s = ut (as a is now 0) gives t = 308.5, so in total it takes t = 316.5s for the car to accelerate from rest to 60km/h and travel 5km from its starting point. similar process for the 50km/h, then just take the difference of the times. lmk if u want me to clarify anything

also sorry if my unit conversions are wrong i did it on my phone calculator lmao (also it’s probably better to use m/s instead of km/s)

 

[Xyzpt]

Oh okay thank you