Question

New Car Lift

A car (mass of 920 kg) is sitting on a car lift in a shop (neglect the mass of the lift itself). While the car is being lifted up, it is slowing down at a rate of 1 m/s². What is the magnitude of the lifting force? (use g = 10 m/s²)

8280. N
-1.012E+04 N
-8280. N
9200. N

Tries 0/1

If the car's initial velocity is 0.3 m/s, what is its final velocity after 3.5 seconds?

m/s

A: -2.05

B: -2.56

C: -3.20

D: -4.00

E: -5.00

Tries 0/1

What is the car's displacement after this 3.5 seconds?

m

A: -3.50

B: -5.08

C: -7.36

D: -10.7

E: -15.5

Answer 1

1 Given mass =920kg and net acceleration = -1m/s²

Here gravity is acting downwards , so Net acceleration = acceleration given - g

-1 = a - 10

a =10 - 1 = 9m/s²

Force given = mass * a

= 920 *9 = 8280 N

ANSWER: Option A

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2 Given u = 0.3m/s and t =3.5 s and a =-1m/s²

use v = u +at

= 0.3 -1 *3.5

v = -3.2m/s

ANSWER : Option C

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(3) From Q(2) we got after 3.5s final velocity = -3.2m/s ,

we know u = 0.3m/s and a =-1m/s²

use formula v²-u² = 2as

3.2² -0.3² = -2 *1*s

s =-10.15/2

s = -5.08 m

ANSWER : Option B