Answer:
Explanation:
Let the distance moved by Joe is "d"
so the time taken by him to drove it by speed 45 mph is given as
now the same distance is traveled by him with speed 55 mph
so the time taken by him
so total time taken by him for complete distance 2d
now the average speed is given as
Answer:
Option B. 8.1
Explanation:
From the question given above, the following data were obtained:
Angle θ = 71°
Hypothenus = 25
Adjacent = x
Thus, we can obtain the x component of the vector by using the cosine ratio as illustrated below:
Cos θ = Adjacent /Hypothenus
Cos 71 = x/25
Cross multiply
x = 25 × Cos 71
x = 25 × 0.3256
x = 8.1
Therefore, the x component of the vector is 8.1
Answer:
12 m/s
Explanation:
divide distance over time
72/6 = 12
solution:
y = v0t + ½at²
1150 = 79t + ½3.9t²
0 = 3.9t² + 158t - 2300
from quadratic equations and eliminating the negative answer
t = (-158 + v158² -4(3.9)(-2300)) / 2(3.9)
t = 11.37 s to engine cut-off
the velocity at that time is
v = v0 + at
v = 79 + 3.9(11.37)
v = 123.3 m/s
it rises for an additional time
v = gt
t = v/g
t = 123.3 / 9.8
t = 12.59 s
gaining more altitude
y = ½vt
y = 123.3(12.59) /2
y = 776 m
for a peak height of
y = 776 + 1150
The magnetic force (Lorentz force) experienced by the proton in the magnetic field is given by
since
, because the velocity v and the force F in this problem are perpendicular, and so also the angle
between the velocity and the magnetic field B should be
.
Let's find the magnitude of the magnetic field; this is given by
To understand the direction, let's use the right-hand rule:
-index finger: velocity
- middle finger: magnetic field
- thumb: force
Since the velocity (index) points east and the force (thumb) points south, then the magnetic field (middle finger) points downwards. So we write:
B = -0.091 T
