#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.
Change in position (triangleV) divided by change in time (triangleT)
Answer:
Force is 14.93N along positive y axis.
Explanation:
We know that force 'F' on a current carrying conductor placed in a magnetic field of intensity B is given by

where L is the length of the conductor
Applying values in the equation we have force F =

Thus force is 14.93N along positive y axis.
Answer:
An element is a pure substance and is made of only one type of atom.
Explanation:
It cannot be broken down into a simpler substance.