#2
As it is given here
initial speed is

After 4 seconds the final speed is

so here we can use the formula of acceleration using kinematics



so here it will accelerate at 2 m/s^2 rate.
#3
As it is given here
initial it starts from rest

After 2.5 seconds the final speed is

so here we can use the formula of acceleration using kinematics



so here it will accelerate at 6 m/s^2 rate.
#4
i think question is not correct as in first line it is saying about a bag of trash and then in next line it is asking for the position of Jumper and bridge.
Answer:
200 kgm/s
Explanation:
momentum = mass x velocity
Answer:
D
Explanation:
From the information given:
The angular speed for the block 
Disk radius (r) = 0.2 m
The block Initial velocity is:

Change in the block's angular speed is:

However, on the disk, moment of inertIa is:

The time t = 10s
∴
Frictional torques by the wall on the disk is:

Finally, the frictional force is calculated as:


Answer:
hello your question is incomplete attached below is the complete question
answer :
a) I1 = I2
b) J1 > J2
c) E 1 > E2
d) ( vd1 ) > ( vd2 )
Explanation:
a) The currents in the two segments are the same i.e. I1 = I2 and this is because the segments are connected in series
b) Comparing the current densities J1 and J2 in the two segments
note : current density ∝ 1 / area
The area of the second segment is > the area of first segment therefore
J1 > J2
J1 ( current density of first segment )
J2 ( current density of second segment )
c) Comparing the electric field strengths E1 and E2
note : electric field strength ∝ current density
since current density of first segment is > current density of second segment and conductivity of the materials are the same hence
E 1 > E2
d) Comparing the drift speeds Vd1 and Vd2
( vd1 ) > ( vd2 )
this because ; vd ∝ current density
An object in motion will stay in motion unless acted upon another force.
Newton used this to prove that gravity existed. Without an unseen force, we could throw a ball and it would go on forever correct? Unless there was something to pull it down, in this case, gravity.