If the object is moving at a constant speed, acceleration is 0. So:

$F = ma

F = m\times 0

F = 0$

The resultant force is 0. So the force pushing the object must be equal to the friction force acting, so

Friction = 90 N

6 0

3 years ago

What are 3 criteria for acceleration?

Temka [501]

I don't think you mean 'criteria'. I think you mean three occurrences or
observations that indicate the presence of acceleration.

They are:

-- an object is speeding up
-- an object is slowing down
-- the direction of an object's motion is changing .

Any one of these changes is acceleration.

There's a single term that covers them all. It is "change in velocity".

3 0

3 years ago

Formula for the distance (d) is given by d = rate*time. For example if you are traveling at 60 mph for 3 hours the distance trav

babunello [35]

Explanation:

Distance covered by the particle is given by:

Distance (d) = rate (v) × time (t)

Speed of Mary, v₁ = 50 mph

Speed of Jim, v₂ = 60 mph

It is assumed that, Mary and Jim leave at the same time. After one hour, Jim is 10 miles ahead.

Distance travelled by Jim, d₁ = (60t + 10)

Distance travelled by Mary, d₂ = 50t

The distance between Mary and Jim is greater than or equal to 100 miles.

$60t+10-50t\ge100$

$10t\ge90$

$t\ge9\ h$

So, Jim takes is 9 hours more than Mary to cover same distance. Hence, this is the required solution.

7 0

2 years ago