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nirvana33 [79]
3 years ago
12

I'm completely lost in physics, the Kinematics and dynamics units.. My exam is coming up.. If a biker travelling at 6.4m/s sees

biker B 34m ahead on the road travelling 4.7m/s. How far will biker B get before biker A catches him?
Physics
1 answer:
Alexeev081 [22]3 years ago
8 0
D=rt
when biker A catches biker B, the time they've been riding is the same, so 
t=t, or d/r=d/r
the rates are 6.4 and 4.7, so
d/6.4=d/4.7
biker B is 34m ahead, so 
(d+34)/6.4=d/4.7
multiply both sides by 6.4*4.7:
4.7(d+34)=6.4d
4.7d+=6.4d+159.8
1.7d=159.8
d=94 meters

Another way to think of it is that biker A gains 1.7 meters on B every second (6.4-4.7=1.5), so the time it'll take for him to gain 34 meters is 34/1.7=20 seconds. In that time, biker B travels 4.7*20=94 meters
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Help plz I don't understand ​
Vika [28.1K]

#78

Airplane start with initial speed

v_i = 0

now the takeoff velocity is given as

v_f = 300 km/h

v_f = 83.33 m/s

acceelration is given as

a = 1 m/s^2

now we have

v_f - v_i = at

from above equation we have

83.33 - 0 = 1(t)

t = 83.33 s

#79

Airplane start with initial speed

v_i = 0

now the takeoff velocity is given as

v_f = 300 km/h

v_f = 83.33 m/s

acceelration is given as

a = 2 m/s^2

now we have

v_f - v_i = at

from above equation we have

83.33 - 0 = 2(t)

t = 41.7 s

6 0
4 years ago
A spiral staircase winds up to the top of a tower in an old castle. To measure the height of the tower, a rope is attached to th
boyakko [2]

Answer:

8.76762 m

Explanation:

T = Time period = 5.94 seconds

g = Acceleration due to gravity = 9.81 m/s²

L = Length of pendulum = Height of tower

Time period is given by

T=2\pi \sqrt{\dfrac{L}{g}}\\\Rightarrow T^2=4\pi^2\dfrac{L}{g}\\\Rightarrow L=\dfrac{T^2g}{4\pi^2}\\\Rightarrow L=\dfrac{5.94^2\times 9.81}{4\pi^2}\\\Rightarrow L=8.76762\ m

The height of the tower is 8.76762 m

8 0
3 years ago
Would you expect to weigh more on an ocean beach or on top of a mountain? Explain.
frosja888 [35]

Answer:

An Ocean beach

Explanation:

a Ocean beach is far heavier than the top of a mountain, despite that a mountain is made with many heavy rocks a Ocean beach may have light sand but the layers of sand and the width would be way heavier then the top of a mountain.

7 0
3 years ago
Which evidence did Ottowa scientists collect in researching PCB concentrations in Alaska?
Sergio [31]
PCBs were found in greater concentrations in lakes where more salmon spawned.
7 0
3 years ago
Read 2 more answers
The driver of a train moving at 23m/s applies the breaks when it pases an amber signal. The next signal is 1km down the track an
pochemuha

Answer:

3.2 m/s

Explanation:

Given:

Δx = 1000 m

v₀ = 23 m/s

a = -0.26 m/s²

t = 76 s

Find: v

This problem is over-defined.  We only need 3 pieces of information, and we're given 4.  There are several equations we can use.  For example:

v = at + v₀

v = (-0.26 m/s²) (76 s) + (23 m/s)

v = 3.2 m/s

Or:

Δx = ½ (v + v₀) t

(1000 m) = ½ (v + 23 m/s) (76 s)

v = 3.3 m/s

Or:

v² = v₀² + 2aΔx

v² = (23 m/s)² + 2(-0.26 m/s²)(1000 m)

v = 3.0 m/s

Or:

Δx = vt − ½ at²

(1000 m) = v (76 s) − ½ (-0.26 m/s²) (76 s)²

v = 3.3 m/s

As you can see, you get slightly different answers depending on which variables you use.  Since 1000 m has 1 significant figure, compared to the other variables which have 2 significant figures, I recommend using the first equation.

8 0
4 years ago
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