Answer:
Kinetic energy is given by:
K.E. = 0.5 m v²
Susan has mass, m = 25 kg
Velocity with which Susan moves is, v = 10 m/s
Hannah has mass, m' = 30 kg
Velocity with which Hannah moves is, v' = 8.5 m/s
<u>Kinetic energy of Susan:</u>
0.5 m v² = 0.5 × 25 kg × (10 m/s)² = 1250 J
<u>Kinetic energy of Hannah:</u>
0.5 m v'² = 0.5 × 30 kg × (8.5 m/s)² = 1083.75 J
Susan's kinetic energy is <u>1250 J </u>and Hannah's kinetic energy is <u>1083.75 J</u>.
Since kinetic energy is dependent on mass and square of speed. Thus, speed has a greater effect than mass. As it is evident from the above example. Susan has greater kinetic energy due to higher speed than Hannah.
Answer:
(a) 153.37 g
(b) 5705 kJ
Explanation:
(a) To find the amount of bean needed by a man you first calculate the equivalence in beans to 2500kJ

Thus, 153.37 g has the energy needed by a man that needs 200kJ per day.
(b) The amount of energy per pot of bean is given by:

Thus, the energy is 5705kJ
This approach is called the dimensional analysis which involves only the units of measurement without their magnitudes. You simply have to do the operations by using variables. Cancel out like items that may appear both in the numerator and denominator side. The solution is as follows:
F = mv²/r = [kg][m/s]²/[m] = [kg][m²⁻¹][1/s²] = [kg·m/s²]
Answer:
17 m/s south
Explanation:
= Mass of dog = 10 kg
= Mass of skateboard = 2 kg
v = Combined velocity = 2 m/s
= Velocity of dog = 1 m/s
= Velocity of skateboard
In this system the linear momentum is conserved

The velocity of the skateboard will be 17 m/s south as the north is taken as positive