Answer:
Lindsey biked 45 miles for 3 hours at 15 mph and walked 8 miles for 2 hours at 4 mph.
Explanation:
Speed = distance/time
Let the distance that Lindsey biked through be x miles and the time it took her to bike through that distance be t hours
Then, the rest of the distance that she walked is (53 - x) miles
And the time she spent walking that distance = (5 - t) hours
Her biking speed = 15 mph = 15 miles/hour
Speed = distance/time
15 = x/t
x = 15 t (eqn 1)
Her walking speed = 4 mph = 4 miles/hour
4 = (53 - x)/(5 - t)
53 - x = 4 (5 - t)
53 - x = 20 - 4t (eqn 2)
Substitute for X in (eqn 2)
53 - 15t = 20 - 4t
15t - 4t = 53 - 20
11t = 33
t = 3 hours
x = 15t = 15 × 3 = 45 miles.
(53 - x) = 53 - 45 = 8 miles
(5 - t) = 5 - 3 = 2 hours
So, it becomes evident that Lindsey biked 45 miles for 3 hours at 15 mph and walked 8 miles for 2 hours at 4 mph.
Explanation:
(c) I assume we're looking for mA.
Sum of forces on B in the -y direction:
∑F = ma
mBg − T = mBa
Sum of forces on A in the +x direction:
∑F = ma
T = mAa
Substitute:
mBg − mAa = mBa
mBg − mBa = mAa
mA = mB (g − a) / a
Plug in values:
mA = (5 kg) (10 m/s² − 0.01 (10 m/s²)) / (0.01 (10 m/s²))
mA = 495 kg
The answer key seems to have a mistake. It's possible they meant mB = 1 kg, or they changed mB to 5 kg but forgot to change the answer.
Answer:
0.06 Kg
Explanation:
From the question given above, the following data were obtained:
Initial velocity (u) = 0 m/s
Final velocity (v) = 3.0 m/s
Distance (s) = 0.09 m
Net Force (F) = 3 N
Mass (m) =?
Next, we shall determine the acceleration of the object. This can be obtained as follow:
Initial velocity (u) = 0 m/s
Final velocity (v) = 3.0 m/s
Distance (s) = 0.09 m
Acceleration (a) =?
v² = u² + 2as
3² = 0² + (2 × a × 0.09)
9 = 0 + 0.18a
9 = 0.18a
Divide both side by 0.18
a = 9 / 0.18
a = 50 m/s²
Finally, we shall determine the mass of the object. This can be obtained as follow:
Net Force (F) = 3 N
Acceleration (a) = 50 N
Mass (m) =?
F = ma
3 = m × 50
Divide both side by 50
m = 3 / 50
m = 0.06 Kg
Therefore, the mass of the object is 0.06 Kg
Answer:
B Negative
Explanation:
Its negative because when your going 25 mph your moving faster and when your coming up to the stop sign you will start to slow down going 10 mph then 0 mph when you reach the stop sign so it will be negative.
Biology, Chemistry and Physics