Answer:
<h3><em>
0.19m/s</em></h3>
Explanation:
velocity is the change in displacement of a body with respect to time. Given the displacement d (m) of a block sliding along a straight line is given by the equation d = -0.65 t + 0.21 t², where t is the time in seconds, instantaneous velocity is expressed by differentiating the displacement with respect to time
Velocity = dd/dt
Velocity = -0.65 + 2(0.21)t²⁻¹
Velocity = -0.65 + 0.42t
The instantaneous velocity of the block when t = 2.0 s can be gotten by substituting t = 2.0s into the expression above:
Velocity = -0.65 + 0.42(2)
Velocity = -0.65 + 0.84
Velocity = 0.19
<em>Hence the instantaneous velocity of the block when t = 2.0 s is 0.19m/s</em>
Mass=33g
volume =30cm^3
density=mass/volume
= 33/30
=1.1g/cm^3 ans
Angular velocity means how many radians/degrees is this hand passing by every second.
First, you realize it goes through a whole revolution (2

in radians) in 60 seconds.
This means for every second, it passes by:

For the next part, you need to know this equation:
Tangential velocity=Angular velocity x radius (meters)

The air drag is a force that depends on the speed of an object relative to the wind. Under certain conditions, it can be modeled as:

Where b is a constant.
As a falling object reaches a speed so that its weight is cancelled out by the air drag, the object will reach a maximum velocity.
In a speed vs time gaph, the speed would approach the maximum speed like an asymptote.
On the other hand, since the object falls from rest, the initial speed on the graph must be zero.
Taking these considerations into account, the correct graph for the movement of an object that falls from rest if air drag is not ignored, is option B.
Answer:
it change speed
Explanation:
its because when light passes through one medium to another (rarer to denser)its velocity change and its speed also changes