Question

Sam, whose mass is 75 kg , takes off across level snow on his jet-powered skis. The skis have a thrust of 160 N and a coefficient of kinetic friction on snow of 0.1. Unfortunately, the skis run out of fuel after only 15 s .
A: What is Sam's top speed?

- I found the answer to be 17 m/s (can you check this for me?)
B: How far has Sam traveled when he finally coasts to a stop? (I have no idea for this one)

Answer 1

Answer:

top speed = 17.25

Total height = 281.19 m

Explanation:

given data

mass = 75 kg

thrust = 160 N

coefficient of kinetic friction = 0.1

solution

we get here frictional force acting that is

frictional force = $\mu *m*g$   .............1

frictional force = 0.1 × 75 × 9.8

frictional force = 73.5 N

and

Net force acting will be F = 160 - 73.5  N

F = 86.5 N

so

Acceleration in the First 15 second  will be

F = ma .........2

86.5 = 75 × a

a = 1.15 m/s²

and

now After 15 second the velocity will be  as

v = u + at   ..........3

here u is 0

so v will be

V = 1.15 × 15

v = 17.25

and

now we get travels distance S  in 15 s

s = u × t + 0.5 × a × t²  

here u is 0

so distance s will be

s = 0.5 × a × t²  

s = 0.5 ×  1.15 × 15²  

s = 129.37 m

and

now  acceleration acting is

F =  $\mu *m*g$  

m a =  $\mu *m*g$

a = $\mu* g$

a = - 0.98

here it is negative it mean downward nature of acceleration

and

now we get distance s by this formula

V² - u² = 2 a s    

here v velocity is 0  and

u initial velocity is 17.25 m/s

put here value

0 - 17.25² = 2 × (-0.98) × s    

solve it we get

s = 151.82 m

so

Total height is

Total height = 129.37 m + 151.82 m

Total height = 281.19 m