22. a - (vf^2 - vi^2)/(2d)
a = (0 - 23^2)/(170)
a = -3.1 m/s^2
23. Find the time (t) to reach 33 m/s at 3 m/s^2
33-0/t = 3
33 = 3t
t = 11 sec to reach 33 m/s^2
Find the av velocuty: 33+0/2 = 16.5 m/s
Dist = 16.5 * 11 = 181.5 meters to each 33m/s speed. Runway has to be at least this long.
24. The sprinter starts from rest. The average acceleration is found from:
(Vf)^2 = (Vi)^2 = 2as ---> a = (Vf)^2 - (Vi)^2/2s = (11.5m/s)^2-0/2(15.0m) = 4.408m/s^2 estimated: 4.41m/s^2
The elapsed time is found by solving
Vf = Vi + at ----> t = vf-vi/a = 11.5m/s-0/4.408m/s^2 = 2.61s
25. Acceleration of car = v-u/t = 0ms^-1-21.0ms^-1/6.00s = -3.50ms^-2
S = v^2 - u^2/2a = (0ms^-1)^2-(21.0ms^-1)^2/2*-3.50ms^-2 = 63.0m
26. Assuming a constant deceleration of 7.00 m/s^2
final velocity, v = 0m/s
acceleration, a = -7.00m/s^2
displacement, s - 92m
Using v^2 = u^2 - 2as
0^2 - u^2 + 2 (-7.00) (92)
initial velocity, u = sqrt (1288) = 35.9 m/s
This is the speed pf the car just bore braking.
I hope this helps!!
Answer:
Explanation:
We shall apply Ampere's circuital law to find out magnetic field . It is given as follows.
∫B.dl = μ₀ I , B is magnetic field , I is current , μ₀ is permeability .
Radius of the wire r = 1.2 x 10⁻³ m
magnetic field B will be circular in shape around the wire. If B is uniform
∫B.dl = B x 2πr
B x 2πr = μ₀ I
B = μ₀ I / 2πr
= 4π x 10⁻⁷ x 37 /2πx1.2 x 10⁻³
= 10⁻⁷ x 2x37 / 1.2 x 10⁻³
= 61.67 x 10⁻⁴ T
= 62 x 10⁻⁴ T
Answer:
The time for the cake to cool off to room temperature is
approximately 30 minutes.
Let 
= 
F be the temperature and T that of the body
Explanation:
Our Tm = 70, the initial-value problem is
= <em>k</em>(T − 70), T(0) = 300
Solving the equation, we get
= <em>kdt</em>
In [T-70]= <em>kt </em>+
T = 70 + 
Finding he value for using the initial value of T (0)= 300, therefore we get:
300=70+
= 230 therefore
T= 70+ 230
Finding the value for <em>k </em>using T (3) = 200, therefore we get
T (3) = 200
= 
<em>K </em>= 
in
= -0.19018
Therefore
T(t) = 70+230
the answer is (A) the movement of the magnet relative to the coil
