Answer:
In an elastic collision, the momentum is conserved and the mechanical energy is conserved too.
Explanation:
There are two types of collisions:
- Elastic collision: in an elastic collision, the total momentum before and after the collision is conserved; also, the total mechanical energy before and after the collision is conserved.
- Inelastic collision: in an inelastic collision, the total momentum before and after the colllision is conserved, while the total mechanical energy is not conserved (in fact, part of the energy is converted into other forms of energy such that thermal energy, due to the presence of frictional forces)
Answer:
Thus, the velocity at the time of strike is same as the velocity at the time of projection.
Explanation:
Let a projectile is projected vertically upwards with a speed of u and reaches to the maximum height H.
At maximum height , the speed is zero and then the projective comes back on the ground.
Use the third equation of motion

Now let the velocity at the time of strike is v'.
Use third equation of motion, here initial velocity is zero.

Thus, the velocity at the time of strike is same as the velocity at the time of projection.
Answer:
-929.5Joules
Explanation:
To get the work done by sam, we will calculate the kinetic energy of sam expressed as;
KE = 1/2mv²
m is the mass = 1100kg
v is the velocity = 1.3m/s
KE = 1/2(1100)(1.3)²
KE = 550(1.69)
KE = 929.5Joules
Since Sam is opposing the direction of movement, work done by him will be a negative work i.e -929.5Joules
Answer:
hmm let's see
Explanation:
ok, ill use the second equation of motion, u see its quite simple
recall that
average velocity= u+v/2
now think of that v like a box you can can call it velocity lol obviously its velocity
now remember the first equation of motion which is
v=u+at now this is inside the box, now you have to replace the v with it
then it becomes u+u+at/2
now u notice there are two initial velocity u know what to do with that
now it becomes
2u + at/2 now since the numerator applies to both then you can simplify it like this
2u/2+at/2
all the same the pont im trying to make is that you can use imaginative ways to mater derivation you can also reverse it if you don't unferstand you can drop your number