Physics help please???!?

You are driving home in your 750-kg car at 15 m/s. At a point 45 m from the beginning of an intersection, you see a green traffic light change to yellow, which you expect will last 4.0 s, and the distance to the far side of the intersection is 65 m.



If you choose to accelerate, your car's engine will furnish a forward force of 1200 N. Will you make it completely through the intersection before the light turns red?



If you decide to panic stop, your brakes will provide a force of 1800 N. Will you stop before entering the intersection?



Can someone please let me know how to do this? I am confused...Physics help please???!?%26lt;%26lt; If you choose to accelerate, your car's engine will furnish a forward force of 1200 N. Will you make it completely through the intersection before the light turns red? %26gt;%26gt;



The analysis here will be as follows -- calculate the distance to be travelled by the car in 4 seconds (after seeing the green light change to yellow). If the distance travelled is greater than 45 m, then the car will make it through the intersection before the light turns red.



Working formula is



S = VoT + (1/2)aT^2



where



S = distance travelled in 4 sec.

Vo = initial velocity = 15 m/sec.

T = 4 seconds

a = acceleration



Substituting values,



S = 15(4) + (1/2)(a)(4^2)



S = 60 + 8a ---- Equation 1



Using Newton's 2nd Law of Motion, F = ma



where



F = force on the car = 1200

m = mass of the car = 750

a = acceleration



and substituting values,



1200 = 750(a)



a = 1.6 m/sec^2



and substituting a = 1.6 m/sec^2 in Equation 1,



S = 60 + 8(1.6)



S = 188 m



YES --- the car can make it safely through the intersection





%26lt;%26lt; If you decide to panic stop, your brakes will provide a force of 1800 N. Will you stop before entering the intersection? %26gt;%26gt;



Using Newton's 2nd Law of Motion,



- 1800 = 750(a)



NOTE the negative sign attached to the force. This is merely to show that the force (braking force) is opposite that of the motion of the car.



a = - 2.4 m/sec^2



Working formula is



S = 15(4) + (1/2)(-2.4)(4^2)



S = 60 - 19.2



S = 40.8 m



Since the car will %26quot;panic%26quot; stop in 40.8 m, it will still stop well ahead of the intersection (which is 45 meters).



Hope this helps.Physics help please???!?First thing you do is determine your acceleration based on the

force values provided F= ma



If you choose to accelerate



1200N =(750kg) a

a = 1.6m/s^2



x = vot + 1/2at^2



x= (15m/s)(4.0)s + 1/2(1.6m/s^2)( 4.0s^2)

x = 72.8m

So you make the light



If you decide to brake



1800N = (750kg)a

a = -2.4m/s^2



x= vot + 12at^2

x= (15m/s)(4.0s) + 1/2(-2.4m/s^2)(4.0^2)

x= 40.8m

So, you're able to stop before intersection

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