1. What is the average speed of a runner that travels 100 meters in 9.7 seconds?

A metal sphere, X, has an initial net charge of −6 × 10−6 coulomb and an identical sphere, Y, has an initial net charge of +2 ×

STatiana [176]

When the two spheres touch each other, part of the charge recombine together. The part of charge that recombines is the excess of positive charge on sphere Y, $Q_y = +2 \cdot 10^{-6}C$ , that recombines with an equivalent charge of $-2 \cdot 10^{-6}C$ located on sphere X. As a result, the total charge remained on the two spheres is the excess of negative charge remained on sphere X:
$Q=-4 \cdot 10^{-6}C$
Since the two spheres are identical, they have same capacity, so this charge will now redistribute equally on the two spheres: therefore, at the end, each sphere will have
$\frac{Q}{2}=-2 \cdot 10^{-6} C$

8 0

3 years ago

Daring Darless wishes to cross the Grand Canyon of the Snake River by being shot from a cannon. She wishes to be launched at 56°

Roman55 [17]

Answer:

She must be launched with a speed of 74.2 m/s.

Explanation:

Hi there!

The equations of the horizontal component of the position vector and the vertical component of the velocity vector are the following:

x = v0 · t · cos θ

vy = v0 · sin θ + g · t

x = horizontal distance traveled at time t.

v0 = initial velocity.

t = time.

θ = launching angle.

vy = vertical component of the velocity vector at time t.

g = acceleration due to gravity (-9.8 m/s²).

To just cross the 520-m gap, the maximum height of the flight must be reached halfway of the gap at 260 m horizontally (see attached figure).

When she is at the maximum height, her vertical velocity is zero. So, when x = 260 m, vy = 0. Using both equations we can solve the system for v0:

x = v0 · t · cos θ

Solving for v0:

v0 = x/ (t · cos θ)

Replacing v0 in the second equation:

vy = v0 · sin θ + g · t

0 = x/(t·cos(56°)) · sin(56°) + g · t

0 = 260 m · tan (56°) / t - 9.8 m/s² · t

9.8 m/s² · t = 260 m · tan (56°) / t

t² = 260 m · tan (56°) / 9.8 m/s²

t = 6.27 s

Now, let's calculate v0:

v0 = x/ (t · cos θ)

v0 = 260 m / (6.27 s · cos(56°))

v0 = 74.2 m/s

She must be launched with a speed of 74.2 m/s.

5 0

3 years ago

Is the following chemical equation balanced? 4Al + 3O2 2Al2O3 yes no

ycow [4]

Answer:no Explanation:

8 0

3 years ago

If the voltage across a circuit of constant resistance is doubled, how is the current in the circuit affected?

Alex73 [517]

Answer:

(e)-The current is doubled.

Explanation:

According to Ohm law, $I = \frac{V}{R}$ where I is the current, V is the voltage and R is the resistant.

$I_1 = \frac{V_1}{R_1}$

$I_2 = \frac{V_2}{R_2}$

If V is doubled, $V_2 = 2V_1$ while R remains constant $R_2 = R_1$ we would have

$I_2 = \frac{2V_1}{R_1} = 2(\frac{V_1}{R_1}) = 2I_1$

The current is doubled.

7 0

4 years ago

What is the difference between rutherford's model of the atom and bohr's model of the atom

Amanda [17]

Answer:

Rutherford described the atom as consisting of a tiny positive mass surrounded by a cloud of negative electrons. Bohr thought that electrons orbited the nucleus in quantised orbits. Bohr built upon Rutherford's model of the atom. ... So it was not possible for electrons to occupy just any energy level.

Explanation:

7 0

3 years ago