Okay, so I suddenly realized Physics isn't the easiest subject to learn but I have so much fun learning it! (but now I am stuck)

tannawirsch:

Okay, so I suddenly realized Physics isn't the easiest subject to learn but I have so much fun learning it! (but now I am stuck)

1. It was recorded that a Jaguar left skid marks which were 290 meters in length. Assuming that the Jaguar skidded to a stop with a constant acceleration of -3.90 m/s^2 , determine the speed of the Jaguar before it began to skid.
*For this question I couldn't figure out what equation to use*
Make a list of what you have
u = initial velocity = unknown
v = end velocity = 0
a = -3.9 m/s²
s = distance travelled = 290m
Look for a formula that has those things
v² = u² +2as
0 = u² + 2*-3.9*290
u² = 2262
u = 47.56 m/s

It has been a life time since I have done these problems but I think that is correct.

and same as with the following question:

2. A dragster accelerates to aspeed of 112m/s over a distance of 398m. Determine the acceleration(uniform) of the dragster.

Also, I need to go over a couple of questions to make sure I got them right.

1. A car traveling along a straight road ata a constant velocity of 20m/s. The driver depresses the acceleration and the velocity of the car changes to 35m/s in the next ten seconds. Calculate the acceleration of the vehicle.

V₁ = 20m/s
V₂ = 35m/s
∆T = 10s
A = ?

A = V₂ - V₁ / ∆T
= (20 - 35 / 10)
= 16.5 m/s^2

2. Calculate the ground velocity of a small boat that can travel 2 m/s in still water but heading East in a river that has a current of 0.5 m/s [S].

Find the direction: tan θ = 0.5 / 2
tan θ = 14˚
V2 = ( 2 m/s )^2 + ( 0.5 m/s )^2
= 4.25
V = √4.25 = 2.06