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Sphinxa [80]
3 years ago
11

A ball dropped from rest falls freely until it hits the ground with a speed pf 20 m/s. The time during with the ball is in free

fall is approximately
Physics
1 answer:
saul85 [17]3 years ago
5 0

Answer:

\large \boxed{\text{2.0 s}}

Explanation:

\begin{array}{rcl}v & = & gt\\\text{20 m$\cdot$s}^{-1} & = & \text{9.807 m$\cdot$ s}^{-2} \times t\\t & = & \dfrac{20}{9.807 \text{ s}^{-1}}\\\\& = & \textbf{2.0 s}\\\end{array}\\\text{The ball is in free fall for $\large \boxed{\textbf{2.0 s}}$}

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Sanjay is making plans for his Saturday afternoon. He can choose a health-enhancing activity like lifting weights, or he can cho
Bezzdna [24]

Answer: Sanjay can burn 100 more calories every 30 minutes if he chooses to lift weights instead of watching tv

Explanation: 133-33= 100 calories (says in article and i just answered it)

7 0
3 years ago
Two resistors A and B are arranged in series in one branch of a parallel arrangement. The other branch contains a single resisto
Ganezh [65]

Answer:

Explanation:

A and B are in series , Total resistance = Ra + Rb

This resistance is in parallel with single resistor C

Equivalent resistance Re = Rc x ( Ra + Rb ) / [Rc + ( Ra + Rb )]

Now this combination is in series in single resistance D .

Total resistance = Rd + Re

= Rd + { Rc x ( Ra + Rb ) / [Rc + ( Ra + Rb )] }

5 0
2 years ago
Timed! I would really appreciate some help! thank you!
GenaCL600 [577]

Answer:

x = 5[km]

Explanation:

We must convert the time from minutes to hours.

t=30[min]*\frac{1h}{60min}= 0.5[h]\\

We know that speed is defined as the relationship between space and time.

v=x/t

where:

x = space [m]

t = time = 0.5 [h]

v = velocity [m/s]

Now replacing:

x = 10[\frac{km}{h} ]*0.5[h]\\x=5[km]

4 0
2 years ago
A 4-kg toy car with a speed of 5 m/s collides head-on with a stationary 1-kg car. After the collision, the cars are locked toget
mihalych1998 [28]

Kinetic energy lost in collision is 10 J.

<u>Explanation:</u>

Given,

Mass, m_{1} = 4 kg

Speed, v_{1} = 5 m/s

m_{2} = 1 kg

v_{2} = 0

Speed after collision = 4 m/s

Kinetic energy lost, K×E = ?

During collision, momentum is conserved.

Before collision, the kinetic energy is

\frac{1}{2} m1 (v1)^2 + \frac{1}{2} m2(v2)^2

By plugging in the values we get,

KE = \frac{1}{2} * 4 * (5)^2 + \frac{1}{2} * 1 * (0)^2\\\\KE = \frac{1}{2} * 4 * 25 + 0\\\\

K×E = 50 J

Therefore, kinetic energy before collision is 50 J

Kinetic energy after collision:

KE = \frac{1}{2} (4 + 1) * (4)^2 + KE(lost)

KE = 40J + KE(lost)

Since,

Initial Kinetic energy = Final kinetic energy

50 J = 40 J + K×E(lost)

K×E(lost) = 50 J - 40 J

K×E(lost) = 10 J

Therefore, kinetic energy lost in collision is 10 J.

4 0
3 years ago
What were four of Galileo’s discoveries that were important to astronomy?
Scorpion4ik [409]

Explanation:

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2. Law of Falling bodies: The acceleration due to gravity is independent of weight of the objects that means two bodies of different mass will hit the ground at the same time if dropped from the same height.

3. The uneven surface of the Moon: He observed that the surface of the Moon is uneven and rough.

4. Discovery of the 4 Moons of Jupiter

7 0
3 years ago
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