Answer:
46
Explanation:
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Density offers a convenient means of obtaining the mass of a body from its volume or vice versa; the mass is equal to the volume multiplied by the density (M = Vd), while the volume is equal to the mass divided by the density (V = M/d).
M = V d
M = 1.4 * 2 = 2.8 kg
Answer:
Velocity, v = 0.239 m/s
Explanation:
Given that,
The distance between two consecutive nodes of a standing wave is 20.9 cm = 0.209 m
The hand generating the pulses moves up and down through a complete cycle 2.57 times every 4.47 s.
For a standing wave, the distance between two consecutive nodes is equal to half of the wavelength.

Frequency is number of cycles per unit time.

Now we can find the velocity of the wave.
Velocity = frequency × wavelength
v = 0.574 × 0.418
v = 0.239 m/s
So, the velocity of the wave is 0.239 m/s.
Connection to Big Idea about energy: Gravity creates gravitational potential energy. Gravitational energy relies on the masses of two bodies and their distance.
Connection to Big Idea about the universe: Gravitational force is exerted by all objects with mass throughout the Universe. It is what keeps the Earth and the planets in orbit around the Sun, and our Solar System in orbit around the centre of the Milky Way. Gravity is one of the forces involved in the birth of stars, their evolution and finally their death.
Connection to Big Idea about Earth: The gravitational force is responsible for many physical properties of Earth and consequently it affects the existence and the properties of living creatures on it. For instance, the existence, the chemical composition and the structure of Earth’s atmosphere was determined by Earth’s gravitational force.