Answer:
1) 3.92 J
2) 1596.08 J
3) 16.3 s ??
Explanation:
Initial Potential energy PE = mgh = 0.5(9.8)(0) = 0 J
Initial Kinetic energy KE = ½mv² = ½(0.5)80² = 1600 J
PE = 0.5(9.8)(0.80) = 3.92 J
KE = 1600 - 3.92 = 1596.08 J
Question 3 is not clear
to the point 80 cm above the ground the flight time is only 0.01 s
The time when the mass strikes ground again will be twice the time gravity takes to reduce the initial velocity to zero
t = 2(80.0 / 9.8) = 16.3 s
would not 80 m above the ground be a much more interesting point to consider?
PE = 0.5(9.8)(80) = 392 J
KE = 1600 - 392 = 1208 J
v₈₀ = √(2(1280) /0.5) = 69.5 m/s
t₈₀ = h/v(avg) = 80 / (½(80 + 69.5)) = 1.07 s
Answer:
D) 3.0
Explanation:
As we know that
So,
Now
T = True weight of object
= mg
= 245 N
W = apparent weight = 200 N
= density of object
Now we use the formula
buoyancy force = True weight - W
600 V (9.8) = 45
V = 0.007653
m = 25 kg
And as we know that
= 3266.7
Now
specific gravity is
= 3.2
Hence, the correct option is d.
momentum p= m x v = 15 x -4 = -60 N.s
Answer:
option C
Explanation:
When the baseball is hit high and far it has some horizontal velocity at the highest point so option an i.e. velocity at the highest point is eliminated.
the baseball act as a projectile at the highest point so, there is always downward acceleration acting on the body. so, option e and d is eliminated.
At the highest point, the vertical velocity is zero and neglecting the air resistance we can say that the velocity of the body is slowest.
Hence, the correct answer is option C