Answer:
The height is 
Explanation:
From the question we are told that
The combined mass of the child and the sled is 
The speed of the sled is 
Generally applying SOHCAHTOA on the slope which the combined mass is down from
Here the length of the slope(L) where the combined mass slides through is the hypotenuses
while the height(h) of the height of the slope is the opposite
Hence from SOHCAHTOA

=> 
Generally from the kinematic equation we have that

Here the u is the initial velocity of the combined mass which is zero since it started from rest
and a is the acceleration of the combined mass which is mathematically evaluated as


=> 
=> 
=> 
=> 
Given:
f1 = 20 Hz
f2 = 20000 Hz
speed of sound at 20 degrees celcius = 343 m/s
Solution:
for f1 = 20 Hz,
Using the equation:
lambda = speed of sound / f1 = 343 / 20 = 17.15 m
For f2:
lambda = speed of sound / f2 = 343 / 20000 = 0.01775 m
Therefore the wavelength range of audible sound in air would be 17.15 m to 0.01775 m.
Answer:
Speed of wave 54 ms⁻¹.
Explanation:
Given data:
Frequency of wave = 60 Hz
Wavelength of wave = 0.90 m
Speed = ?
Solution:
Formula
speed = wavelength × frequency
Now we will put the values in formula.
v = f × λ
Hz = s⁻¹
v = 60 s⁻¹ × 0.90 m
v = 54 m s⁻¹
Explanation:
It is given that,
Potential difference between the ends of a rod, V = 1.1 V
Length of the rod, l = 10 cm = 0.1 m
Area of cross section of the rod, 
The resistivity of graphite, 
(a) Let R is the resistance of the rod. It is given by :



So, the resistance of the rod is 0.833 ohms.
(b) Let I is the current flowing in the wire. It can be calculated using the Ohm's law as :


I = 1.32 A
(c) Let E is the electric field inside the rod. The electric field in terms of potential difference is given by :


E = 11 V/m
Hence, this is the required solution.