Answer:
(A) it's acceleration is negative but but it's velocity is positive
Explanation:
In the question it is given that begins to slow down so its speed is decreasing it is does not means that its speed is negative
For example let first the velocity of the car is 30 m/sec and when its velocity decreases it becomes 20 m/sec in 5 sec
So it is not negative at all
Now the acceleration is the rate of change of velocity


So acceleration is negative here
So option (a) will be the correct option
Answer:
2.11 seconds
Explanation:
We use the kinematic equation for the velocity in a constantly accelerated motion under the acceleration of gravity (g):

In order of increasing frequency: Radio, Microwaves, Infrared, Visible light, Ultra-violet, X-rays, Gamma rays. To remember this try:
Rabbits
Mates
In
Very
Unusual
e(X)pensive
Gardens
Hi!
The energy of the block is 4 m/s
To calculate this, you need to use the equation for
kinetic energy. The block is sliding (i.e. it's moving). If the object is sliding across a level surface, the only energy it has is kinetic energy, because
there is no change in potential energy (which changes with height). So, the mechanical energy will be pure kinetic energy. The equation is the following, derived from the expression for kinetic energy:

Have a nice day!