Solve Kinematics Problem: Car & Truck Displacement at Intersection

AI Thread Summary
A car accelerates from rest at 1.8 m/s² when the light turns green, while a truck approaches the intersection at a constant speed of 8.5 m/s. The key to solving the problem involves using the formula d = v_i t + 1/2 at² to determine the car's displacement when it passes the truck. The discussion emphasizes the importance of understanding the car's curved displacement-time graph due to its acceleration. Ultimately, the user successfully solves the problem after receiving guidance on the equation, highlighting the value of collaborative problem-solving.
Washable_Marker
Messages
12
Reaction score
0
Hello, thanks for reading =)

Let's just jump into it...
At the instant the light turns green, a car accelerates from rest at a rate of 1.8m/s^2. A truck gets to the intersection by the time the light changes [and therefore doesn't have to stop]. The truck is traveling at a constant velocity of 8.5m/s.

What will be the displacement of the car [assuming the intersection is 0] when it passes the truck, and at what time will this occur?

----------------

I've been trying to solve it by using a displacement-time graph, but obviously the car will have a curved graph, and I can't figure out the equation of it's line. Any tips on how to go about this, as well as tips to solve the question would be great.

Thanks!
 
Physics news on Phys.org
you will find this formula useful:
d = v_i t + 1/2at^2
 
Aha! Just what I was looking for, and thanks for not giving me the answer outright, it made it much more rewarding to get the right answer.

Thanks again!
 
Did you get the right answer? And I'm glad you appreciate when people don't just give away the solution. :)
 
Yep, got it. That was all I needed for it to click in my brain.
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Help with question on motion: Avoiding a rear-end collision
Replies
6
Views
3K
Car Crash Analysis: Analyzing Friction & Speed
Replies
9
Views
4K
Determining position of an object after inelastic collision
Replies
1
Views
2K
Solve Kinematics Problem: Car Overtaking Truck
Replies
3
Views
2K
Pushing a stalled car out of an intersection
Replies
1
Views
2K
How long does it take for the car to catch up to the truck on a straight track?
Replies
19
Views
2K
Physic (kinematics) — Displacement of an accelerating car
Replies
7
Views
3K
Kinematics Problem: Train braking and blocking an intersection
Replies
1
Views
1K
Kinematics - identifying and describing types of motion
Replies
2
Views
2K
Calculating the Time for a Car Chase: Kinematics Question
Replies
4
Views
3K

Hot Threads

Recent Insights

Back
Top