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Snowcat [4.5K]
3 years ago
7

A student throws a set of keys vertically upward to his fraternity brother, who is in a window 3.60 m above. The brother's outst

retched hand catches the keys 1.60 s later. (Take upward as the positive direction. Indicate the direction with the sign of your answer.)With what initial velocity were the keys thrown?
Physics
1 answer:
Contact [7]3 years ago
5 0

Answer:

v_{i}=10.10 m/s

Explanation:

The equation of the position is:

y=y_{i}+v_{i}t-0.5gt^{2}

Where:

v(i) is the initial velocity

The initial position y(i) will be zero and the final position y = 3.60 m.

So, we just need to solve this equation for v(i).

v_{i}=\frac{y+0.5gt^{2}}{t}

v_{i}=\frac{3.6+0.5*9.81*1.6^{2}}{1.6}

v_{i}=10.10 m/s

Therefore, the initial velocity is 10.10 m/s upwards.

I hope it helps you!

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A student walks 3.0m [E] and then 4.0m [N] in 5.0s.
ANEK [815]

Answer:

average speed and velocity are 0.5m/s (squared)

8 0
3 years ago
What is true about the velocity of sound waves in solids compared to air?
ivolga24 [154]
<h2>The correct option is (A)</h2>

Explanation:

Travels faster in solids because the particles are closer together.

The reason for the above statement is -

(i) Sound waves travel through the medium (solid, Liquid, and gas), more denser is the medium more is the speed of sound.

(ii) In solid, the particles are arranged very closely and tightly packed therefore the sound waves in solid have the fastest speed or travels fastest in comparison to liquid and gas.

(iii) Slower than solid is the travel of sound waves in liquid than in gas(least dense, particles are far apart.

4 0
3 years ago
Which of the following is best described as an inclined plane twisted into a spiral?
melamori03 [73]
It is a screw. Hope this helps!
6 0
3 years ago
A hotel elevator ascends 200m with maximum speed of 5m/s. Its acceleration and deceleration both have a magnitude of 1.0m/s2. Pa
ValentinkaMS [17]

Answer:

45 s .

Explanation:

The accelerator will first accelerate , then move with uniform velocity and at last it will decelerate to rest .

displacement s = ?

acceleration a = 1 m /s²

Final speed v = 5 m/s

initial speed u = 0

v² = u² + 2as

5² = 0 + 2 x 1 x s

s = 12.5  m

B)  Let time of acceleration or deceleration be t

v = u + a t

5 = 0 + 1 t

t = 5 s

Similarly displacement during deceleration = 12.5 m

Total distance during uniform motion = 200 - ( 12.5 + 12.5 ) =  175 m .

velocity of uniform motion = 5 m /s

time during which there was uniform velocity = 175 / 5 = 35 s

Total time = 5 + 35 + 5 = 45 s .

4 0
3 years ago
A simple pendulum is used to determine the acceleration due to gravity at the surface of a planet. The pendulum has a length of
SVEN [57.7K]

Answer:

Acceleration due to gravity is 20 m/sec^2

So option (E) will be correct answer

Explanation:

We have given length of the pendulum l = 2 m

Time period of the pendulum T = 2 sec

We have to find acceleration due to gravity g

We know that time period of pendulum is given by

T=2\pi \sqrt{\frac{l}{g}}

2=2\times 3.14 \sqrt{\frac{2}{g}}

0.3184= \sqrt{\frac{2}{g}}

Squaring both side

0.1014= {\frac{2}{g}}

g=19.71=20m/sec^2

So acceleration due to gravity is 20 m/sec^2

So option (E) will be correct answer.

8 0
3 years ago
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