Asked Dec 12, 2019

The acceleration of a car s after starting from rest is (75+10t-t2)/20 until the instant when this expression vanishes. After this instant the speed remains constant. 

A.Find the maximum acceleration

B. Time taken to attain the greatest speed

C.The greatest speed. 


Expert Answer

Step 1

(A) The acceleration of the car is maximum, when its derivative is zero.

Write the expression for the expression for derivative of acceleration


Image Transcriptionclose

da dt d( 75 +10t – t? dt 20 10 – 2t = 0 20 t = 5 s

Step 2

Substitute the value of time in the given acceleration expression


Image Transcriptionclose

75+10t – t? amax 20 /1=5s 75 +10(5 s) - (5) 20 = 4 m/s?

Step 3

When the car attains a maximum speed, its acceleration is...


Image Transcriptionclose

a = 0 75 +10t – t? = 0 20 -10 + (10) – 4(-1)(75) 2(-1) =-5 s or 15 s


Want to see the full answer?

See Solution

Check out a sample Q&A here.

Want to see this answer and more?

Solutions are written by subject experts who are available 24/7. Questions are typically answered within 1 hour.*

See Solution
*Response times may vary by subject and question.
Tagged in




Related Physics Q&A

Find answers to questions asked by student like you
Show more Q&A

Q: find the atomic mass of oxygen

A: Click to see the answer


Q: A steel cable with total length 30 m and mass 100 kg is connected to two poles. The tension in the c...

A:  Given:Length = 30 mMass = 100 kgTension = 3000 NFrequency = 2 Hz Given:Length = 30 mMass = 100 kgTe...


Q: 4. In Figure 37.7, show mathematically how many interference 7. maxima are enclosed by the central d...

A: Given,


Q: how to answer part b

A: (b). given that the pressure at point A is five time that of point C, then it can be written as,


Q: A water pipe having a 2.59 cm inside diameter carries water into the basement of a house at a speed ...

A: Consider the radius of the pipe at the first end be r1, the radius of the pipe at the other end be r...


Q: arrow_forward   Question Asked Dec 11, 2019 One end of a spring is fixed to th...

A: Total distance the block travels along the incline is given by,


Q: A weight lifter lifts a 330-N set of weights from ground level to a position over his head, a vertic...

A: Given:Weight = force = 380 NDistance = 1.75 m 


Q: 89. A 5.00-g bullet mov- AMT ing with M speed of v; = 400 m/s is fired into and passes Vi an initial...

A: Consider the bullet’s mass be m, the block’s mass be M, the initial speed of the block be vbi, and t...


Q: 134. As an object falls freely toward Earth, the object's momentum (1) decreases (2) increases (3) r...

A: Object falls freely toward earth.