Answer:
24.2 s
29.2 m
Explanation:
First, convert each speed from km/h to m/s.
91.5 km/h = 25.42 m/s
77.5 km/h = 21.53 m/s
The speed of the cheetah relative to the gazelle is:
v = 25.42 m/s − 21.53 m/s
v = 3.89 m/s
So the time it takes for the cheetah to catch the gazelle is:
x = v t
94.2 m = (3.89 m/s) t
t = 24.2 s
If instead we want to find x so that t = 7.5 s, then:
x = v t
x = (3.89 m/s) (7.5 s)
x = 29.2 m
Answer: Decreases
Explanation:
By definition, absolute zero temperature defines the temperature at which the atoms of a material no longer transmit thermal energy.
Engineering materials can transmit thermal energy at higher temperatures by random molecular motion.
It follows that as the temperature decreases toward absolute zero, random molecular motion decreases.
Q = m * c * ΔΤ
ΔΤ = 40-20 = 20
Q = 1.5kg * 0.9 * 20
Q = 27J
Answer: d
Explanation:
mass of truck mt, kinetic energy of truck Ekt(Kt), Vt -speed of truck
mass of car ma, kinetic enregy of car Ekc(Kc), Vc-speed of car
mass of truck mt=2*mc
speed of truck Vt=2*Vc
Compare Kinetic energy of truck with kinetic energy of car using equation to calculatation ;
Kinetic energy of car:
Kc=(mc*Vc²)/2
Kinetic energy for truck:
Kt=(mt*Vt²)/2
Kt=((2*mc*(2*Vc)²)/2
Kt=(2*mc*4*Vc²)/2
Kt=8*mc*Vc²/2
Compare Kinteic energy truck with Kinetic energy of car:
Kt/Kc
Kt/Kc=((8*mc*Vc²)/2)/((mc*Vc²)/2)
Kt/Kc=8
