Answer:
Explanation:
a ) Let let the frictional force needed be F
Work done by frictional force = kinetic energy of car
F x 107 = 1/2 x 1400 x 35²
F = 8014 N
b )
maximum possible static friction
= μ mg
where μ is coefficient of static friction
= .5 x 1400 x 9.8
= 6860 N
c )
work done by friction for μ = .4
= .4 x 1400 x 9.8 x 107
= 587216 J
Initial Kinetic energy
= .5 x 1400 x 35 x 35
= 857500 J
Kinetic energy at the at of collision
= 857500 - 587216
= 270284 J
So , if v be the velocity at the time of collision
1/2 mv² = 270284
v = 19.65 m /s
d ) centripetal force required
= mv₀² / d which will be provided by frictional force
= (1400 x 35 x 35) / 107
= 16028 N
Maximum frictional force possible
= μmg
= .5 x 1400 x 9.8
= 6860 N
So this is not possible.
Answer:
Force is 57.69 N to the opposite direction of motion of dolphin.
Explanation:
We have force is the product of mass and acceleration.
That is
Force = Mass x Acceleration
F = ma
Mass of dolphin, m = 30 kg
We have equation of motion, v = u + at
Final velocity, v = 7 m/s
Initial velocity, u = 12 m/s
Time, t = 2.60 s
Substituting
7 = 12 + a x 2.6
a = -1.92 m/s²
Force, F = 30 x -1.92 = -57.69 N
So the force is 57.69 N to the opposite direction of motion of dolphin.
Answer:
Option D 3.9
Explanation:
First, you need to use the correct equation which is the following:
COP = Q/W
Where:
Q = heat absorbed
W = work done by the pump
COP = coefficient of perfomance
We have all the data, so, all you need to do is replace in the above expression and you shoould get the correct result:
COP = 30 / 7.7
COP = 3.896
This result you can round it to 3.9. option D.
We have: K.E. = 1/2 mv²
Here: m = 50 g = 0.05 Kg
v = 4 m/s
Substitute their values,
K.E. = 1/2 * 0.05 * 4²
K.E. = 1/2 * 0.05 * 16
K.E. = 0.4 J
In short, Your Answer would be 0.4 Joules
Hope this helps!
