Physics

A flatbed truck with a box sitting on the bed accelerates from rest on level ground. The truck’s speed as a
function of time is 15t –2t^2 during this acceleration. The truck reaches its maximum speed and cruises along at this speed for 4 minutes. It then slows to a stop with an acceleration of 2 m/s/s.
a) What is the net force as a function of time, acting on the truck during the speeding up portion?
b) What is the maximum speed the truck attains?
c) At what time does the truck reach maximum speed?
d) How far does the truck travel during the entire trip?
e) How much work is done on the 588 N box in the bed of the truck while speeding up?
f) What force does that work on the box?
g) How much total work is done on the box during the entire trip?

  1. 👍 0
  2. 👎 0
  3. 👁 112
  1. v=15t-2t²
    a=dv/dt = 15 - 4t.
    (a)F=m•a=m• (15-4t),

    For finding v(max):
    a=15 - 4t=0
    15=4t
    (c) t=15/4 (s)

    (b)v(max)=15t-2t² =
    =15•15/4 -2•(15/4)²=28.125 m/s.

    (d) s1=∫(15t-2t²)dt=15t²/2 – 2t³/3 =
    =15•15²/2•4² -2•15³/3•4³ = 70.31 m.
    s2 = v(max) •t=28.125•4•60=6750 m.
    s3= v²/2a=(28.125)²/2•2 = 197.8 m

    s1+s2+s3 = 70.31+6750+197.8 =7018 m.

    (e) The work of the net force during the sppeding up portion
    W1=ΔKE=mv²/2=(588/9.8) •28.125²/2=2.37•10^4 J.
    (f) F=m•a=m• (15-4t),
    (g) W2=0 (since the net force is zero),
    W3=ΔKE =0- mv²/2=0-(588/9.8) •28.125²/2=
    =0-2.37•10^4 J= - 2.37•10^4 J.
    W=W1+W2+W3=0

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. engineering physics 1-science

    A crate of mass m(=32 kg) rides on the bed of a truck attached by a cord to the back of the cab . The cord can withstand a maximum tension of 68N before breaking. Neglecting friction between the crate and the truck bed, find the

    asked by Endes Nalabaw on August 9, 2015
  2. Physics

    A truck carrying a 38 kg crate accelerates uniformly from rest to 87.5 km/hr in 12.1 s. Calculate the work done on the crate by the truck. Please help:/

    asked by Caddy on October 19, 2012
  3. Physics

    A 225 kg box is loaded onto a truck by pulling it up an inclined plane (10 m hypotenuse difference) by a force that is parallel to the incline (T = 315 N). If the bed of the truck is 1.2 m above the ground what is the efficiency

    asked by Matt on April 7, 2011
  4. Physics

    You're driving your pickup truck around a curve with a radius of 22meters. A box in the back of the truck is pressed up against the wall of the truck. -How fast must you drive so that the force of the wall on the box equals the

    asked by Noe Valencia on October 24, 2011
  5. applied physics

    the work required to lift eleven 94.0lb bags of cement from the ground to the back of a truck is 4340ft lb. what is the distance from the ground to the bed of the truck?

    asked by donna on April 22, 2013
  1. physics

    A 125 kg crate rests on the flatbed of a truck that moves at a speed of 15.0 m/s around an unbanked curve whose radius is 66.0m. This crate does not slip relative to the truck. Obtain the magnitude of the static frictional force

    asked by Lynda on November 3, 2010
  2. physics

    A crate rests on a flatbed truck which is initially traveling at 17.8 m/s on a level road. The driver applies the brakes and the truck is brought to a halt in a distance of 33.1 m. If the deceleration of the truck is constant,

    asked by confused on October 2, 2014
  3. physics

    A crate of mass 45.0 kg is being transported on the flatbed of a pickup truck. The coefficient of static friction between the crate and the truck's flatbed is 0.360, and the coefficient of kinetic friction is 0.160. (a) The truck

    asked by Anonymous on September 29, 2012
  4. physics

    A crate is resting on the bed of a moving truck. the coefficient of static friction between the crate and the truck bed is 0.40. the driver hits the brakes. assuming the truck is traveling on level ground, determine the maximum

    asked by ajo on December 1, 2007
  5. Physics

    A pickup truck is carrying a toolbox, but the rear gate of the truck is missing, so the box will slide out if it is set moving. The coefficients of kinetic and static friction between the box and the bed of the truck are 0.340 and

    asked by Braum on February 16, 2017
  6. Physics

    A truck is traveling at a speed of 23.0 m/s along a level road. A crate is resting on the bed of the truck, and the coefficient of static friction between the crate and the truck bed is 0.610. Determine the shortest distance in

    asked by Donna on October 4, 2013

You can view more similar questions or ask a new question.