Answer:
true
Explanation:
Friction occurs because no surface is perfectly smooth. Rougher surfaces have more friction between them. Heavier objects also have more friction because they press together with greater force. Friction produces heat because it causes the molecules on rubbing surfaces to move faster and have more energy.
Answer:
time taken with speed 23 km/h will be 1.8 hours or 1 hour 48 minutes
Explanation:
Given:
Time is inversely proportional to the speed
mathematically,
t ∝ (1/r)
let the proportionality constant be 'k'
thus,
t = k/r
therefore, for case 1
time = 3 hr
speed = 14 km/hr
3 = k/14
also,
for case 2
let the time be = t
r = 23 km/h
thus,
we have
t = k/23
on dividing equation 2 by 1
we get

or

or
t = 1.8 hr = or 1 hour 48 minutes ( 0.8 hours × 60 minutes/hour = 48 minutes)
Answer:
Acceleration of the second particle at that moment is given as

Explanation:
As we know that both cars are connected by same spring
So on this system of two cars there is no external force
So we will have

now we have



now we have

so we have

Friction produces heat hope this helps
The correct answer (d.) epistemology. The major contribution of the French philosopher Rene Descartes was in the realm of epistemology. Epistemology is the theory of knowledge, including methods, validity, and its scope. It could also be concluded to separate justified fact from an opinion.