Answer:
8977.7 kg/m^3
Explanation:
Volume of water displaced = 55 cm^3 = 55 x 10^-6 m^3
Reading of balance when block is immersed in water = 4.3 N
According to the Archimedes principle, when a body is immersed n a liquid partly or wholly, then there is a loss in the weight of body which is called upthrust or buoyant force. this buoyant force is equal to the weight of liquid displaced by the body.
Buoyant force = weight of the water displaced by the block
Buoyant force = Volume of water displaced x density of water x g
= 55 x 10^-6 x 1000 x .8 = 0.539 N
True weight of the body = Weight of body in water + buoyant force
m g = 4.3 + 0.539 = 4.839
m = 0.4937 kg
Density of block = mass of block / volume of block
= 
Density of block = 8977.7 kg/m^3
I am quite sure the first one is Friction, but I am not sure about the second one. Is it wind?
Answer:
No
Explanation:
She will not be able to measure the length of her window accurately due to instrumental error from her choice of instrument. The elastic nature of her tape would alter the measurement because it will stretch as she is taking her readings, thus reducing the true measurement of the length of her window.
To measure the length of her window, she could use an inelastic tape rule or a metre rule. These instruments would eliminate instrumental error.
The answer is
Pitch of the buzzer increased (higher tone) as it moves towards the observer
Explanation:
Usually when we think of waves, we think of transverse waves. These are waves where points move up and down perpendicular to the motion of the wave. Examples include water waves, whipping a rope, or even doing the "wave" in a crowd. You can think of these as "two dimensional" waves.
Longitudinal waves are waves where points move left or right, parallel to the motion of the wave. In other words, there is compression and expansion of the medium. Examples include sound waves, or pulses in a slinky.
