They can't hear an echo in small room because in it the sound can't be reflected back. For an echo of a sound to be heard,the minimum distance between the source of sound and the walls of the roomshould be 17.2 m. Obviously,in asmall room echoes cannot beheard.
Answer:
Granite
Explanation:
Trust me I learned this 2years ago
We know the equation
weight = mass × gravity
To work out the weight on the moon, we will need its mass, and the gravitational field strength of the moon.
Remember that your weight can change, but mass stays constant.
So using the information given about the earth weight, we can find the mass by substituting 100N for weight, and we know the gravity on earth is 10Nm*2 (Use the gravitational field strength provided by your school, I am assuming yours in 10Nm*2)
Therefore,
100N = mass × 10
mass= 100N/10
mass= 10 kg
Now, all we need are the moon's gravitational field strength and to apply this to the equation
weight = 10kg × (gravity on moon)
Answer:14 m/s
Explanation:
Kinetic energy(ke)=175J
Momentum(M)=25kgm/s
Speed=v
Mass=m
Ke=(m x v x v)/2
175=(mv^2)/2
Cross multiply
175 x 2=mv^2
350=mv^2
Momentum=mass x velocity
25=mv
m=25/v
Substitute m=25/v in 350=mv^2
350=25/v x v^2
350=25v^2/v
v^2/v=v
350=25v
v=350/25
v=14 m/s