Answer:
Acceleration will be 
Explanation:
We have given initial speed of the car is 70 km/hr
We know that 1 km = 1000 m
And 1 hour = 3600 sec
So 
It is given that car stops in 12 sec
So final speed of the car v = 0 m/sec
Time t = 12 sec
From first equation of motion v = u+at
So 
( negative sign indicates that speed of the car will constantly decrease )
Answer:
C.) A high velocity and Large mass.
Explanation:
Momentum of any object is defined by following formula
Here
: m = mass of object
v = velocity of object
now we know that since momentum is product of mass and velocity
So in order to have more momentum we need the value of this product to be more. So this product will me large is both the physical quantity will be more in magnitude. So if mass is large and velocity will be more then the product of them will be large and hence the momentum of object will be more. Btw I had that question too.
Answer:
A) Impulse is the same for both the objects
B) The higher is the speed, the greater will be the height.
Explanation:
Part a)
The time of interaction of the two bodies i.e the hanging mass and the stick is same. Thus, force caused by dart on the block = force caused by block on the dart. Hence, impulse is the same for both the objects.
Part B
The energy will be conserved in the entire reaction process
Hence, Kinetic energy = potential energy
0.5Mv^2 = gh(md+mb)
H is directly proportional to the square of speed.
Hence, the higher is the speed, the greater will be the height.
Hooke's Law states that the extension is directly proportional to the force applied so:
F/x = constant
F₁/x₁ = F₂/x₂
2 / 0.02 = 1600 / x₂
x₂ = 16 m
Elastic work = 1/2 Fx
= 1/2 * 1600 * 16
= 12.8 kJ
Probably because of the drag coefficient and the density of the liquid.
