The following pairs of surfaces are pushed together with the same amount of force. Between which pair of surfaces will friction
2 answers:
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Answer:The frequency of the echo is slightly decreased
Explanation:
Given
speed of boat
cliff is away
when boat is still , suppose t is the time taken by the echo to reach observer on the boat
But as soon as boat starts moving the distance between cliff and boat decreasing and time for echo to reach observer also decreases
and we know
therefore frequency of the echo slightly decreased.
<h2>Δt = 71.67 °C</h2>
The temperature change of water is equal to 71.67 °C
<h3>Explanation:</h3>
Given:
Amount of transferred energy = 30,000 K J
Mass of water = 100 ml
Initial temperature = 20°C
To find the change in temperature of water.
Formula for Heat capacity is given by
Q = m×c×Δt ........................................(1)
where:
Q = Heat capacity of the substance (in J)
m=mass of the substance being heated in grams(g)
c = the specific heat of the substance in J/(g.°C)
Δt = Change in temperature (in °C)
Δt = (Final temperature - Initial temperature) = T(f) - T(i)
Q = 30,000 J
Mass of water = m = 100 ml
1 ml = 1 g ................................................(2)
Therefore m = 100 ml = 100 g
Specific heat of water is c = 4.186 J /g.
Δt = ?
Substituting these in equation (1), we get
Q = m×c×Δt
Rearranging the terms for Δt,
Δt =
Δt =
Δt = 71.67 °C