Answer:
111.5 m
Explanation:
Given that You are driving to the grocery store at 14 m/s. You are 115 m from an intersection when the traffic light turns red. Assume that your reaction time is 0.50 s and that your car brakes with constant acceleration.
Use first equation of motion
V = U - at
Since the car is going to rest, V = 0 and a = negative
0 = 14 - a × 0.5
0.5a = 14
a = 14 /0.5
a = 28 m/s^2
Let us use second equation of motion
S = Ut - 1/2at^2
S = 14 × 0.5 - 0.5 × 28 × 0.5^2
S = 7 - 3.5
S = 3.5 m
115 - 3.5 = 111.5
Therefore, you are 111.5 metres from the intersection (in m) when you begin to apply the brakes.
Answer:
L = 41.09 Kg m2 / s The angular momentum does not depend on the time
Explanation:
The definition of angular momentum is
L = r x p
Where blacks indicate vectors
Let's apply this definition our case. Linear momentum
p = m v
Let's replace
L = m r x v
The given function is
x = 6.00 i ^ + 4.15 t j
^
We look for speed
v = dx / dt
v = 0 + 4.15 j ^
To evaluate the angular momentum one of the best ways is to use determinants
![L = m \left[\begin{array}{ccc}i&j&k\\6&4.15t&0\\0&4.15&0\end{array}\right]](https://tex.z-dn.net/?f=L%20%3D%20m%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Di%26j%26k%5C%5C6%264.15t%260%5C%5C0%264.15%260%5Cend%7Barray%7D%5Cright%5D)
L = m 6 4.15 k ^
The other products give zero
Let's calculate
L = 1.65 6 4.15 k ^
L = 41.09 Kg m2 / s
The angular momentum does not depend on the time
Answer:
Explanation:
Deceleration of solid disk = g sin10/1 + k²/r² = g sin 10 / 1 + 1/2 = g sin 10 x 2/3
[ k is radius of gyration of disk which is equal to( 1/√2)x r ]
deceleration a = -1.1345 m/s²
v = u - at , t = u / a = 1.5 / 1.1345 = 1.322 s.
Answer: object B is negatively charged, object C is positively charged and object D is also positively charged
Explanation: since unlike charges attract and like charges repel, for object A which is positively charged and B to attract B must be negatively charged and then for B which is negatively charged and C to attract C must be positively charged and for C and D to repel they have to be of thesame charge which means D is positive as well.
