You are holding a briefcase by the handle, with your arm straight down by your side. Does the force your hand exerts do work on the briefcase when (a) you walk at a constant speed down a horizontal hallway and (b) you ride an escalator from the first to second floor of a building? In both cases justify your answer.

Q: How much work does an elevator motor do raising a mass of 1176 kg vertically 15.3 m? I solved this…

A: To raise the mass the elevator motor must work against gravity. From conservation of energy the work…

Q: A cable exerts a constant upward tension of magnitude 1.54 x 10 N on a 1.40 x 10 kg elevator as it…

A: According to question--- Given data-- Tension  = 1.54 × 104 N. Mass of elevator m = 1.40 × 103 kg.…

Q: An asteroid is moving along a straight line. A force acts along the displacement of the asteroid and…

A: Mass of an asteroid = 5.5Initial speed of asteroid = 7000 m/sFinal speed of asteroid = 5500…

Q: In the figure, a 0.23 kg block of cheese lies on the floor of a 880 kg elevator cab that is being…

A:

Q: A 313 kg crate hangs from the end of a rope of length L = 10.6 m. You push horizontally on the crate…

A: According to the given condition,  we have to hold the crate in the final situation, hence F ( force…

Q: che crate and the ground)

A:

Q: In the figure, a constant external force P= 160 N is applied to a 20.0-kg box, which is on a rough…

A:

Q: A 50 kg trunk is pushed 6.0 meters at constant speed up a 30 degree incline by a constant horizontal…

A:

Q: A worker pushes a m = 2.60 kg carton a distance d = 7.20 m along the floor by a constant force of…

A:

Q: A 350 kg sofa slides 2.5 m down a 30° incline and who is pushing back on it parallel to the incline…

A: Given:- The mass of the sofa m = 350 kg  The sliding length L = 2.5 m  The angle of the incline is…

Q: In the figure below, a 0.250 kg block of cheese lies on the floor of a 891 kg elevator cab that is…

A:

Q: As shown in the figure, the package of mass m = 3.00 kg initially resting at x = 0 on a roller belt…

A: Mass of the package is 3.00 kg

Q: A dock worker pushes a m = 3.60 kg crate a distance d = 6.60 m along the floor by a constant force…

A:

Q: A cable exerts a constant upward tension of magnitude 2.30 x 104 N on a 2.00 x 10° kg elevator as it…

A: (given)      Force (F) = 2.30 × 104 N      Mass (m) = 2.00 × 103 kg Distance (d) = 4.10 m (a)  Work…

Q: In the figure, a 0.24 kg block of cheese lies on the floor of a 970 kg d₁ = 3.0 m and then through…

A:

Q: A skier is pulled by a tow rope up a frictionless ski slope that makes an angle of 20° with the…

A: Given: Skier moves with constant velocity. Distance moved up the ramp = 6.7 m Speed 1 = 0.99 m/s…

Q: In the figure, a 0.25 kg block of cheese lies on the floor of a 900 kg elevator cab that is being…

A:

Q: In a shipping yard, a crane operator attaches a cable to a 1,340 kg shipping container and then uses…

A:

Q: Starting from rest, a 4.2-kg block slides 2.20 m down a rough 30.0° incline. The coefficient of…

A: Given Data: The mass of  a block is, m=4.2 kg The distance at which box slides is, d=2.20 m The…

Q: A hummingbird is able to hover because, as the wings move downward, they exert a downward force on…

A: Given data: The wings move through a distance =2.9 cm The wings beats = 85 times per second The mass…

Q: A 70 kg rollerblader skates across a skating rink floor. The graph below shows the net external…

A: Write the expression for the work done. W=F→⋅d→W=FdcosθW=(Fcosθ)(d)

Q: In which of these situations is work being done? A B C D You sit in a chair reading your textbook.…

A: Solution: Given: In which of these situations is work being done? A. You sit in a chair reading your…

Q: A cord is used to vertically lower an initially stationary block of mass M = 13 kg at a constant…

A:

Q: 5.1. A 5.0 kg weight falls past a window that is 1.5 m in vertical length. (a) How much work does…

A: Mass of weight,                   Height of window,

Q: An asteroid is moving along a straight line. A force acts along the displacement of the asteroid and…

A: Initial speed (u) = 7100 m/s Final speed (V) = 4900 m/s Mass = 48000 Kg distance = 2000000 m   a)…

Q: A box is supported by a 4.6 N vertical force and carried 2.3 m horizontally across a room at…

A: Force F = 4.6 N Displacement x = 2.3 m

Q: A roller-coaster car of mass 1.50 × 103 kg is initially at the top of a rise at point Ⓐ. It then…

A: Given,

Q: The work done on the box by the normal force of the plane is zero joules. The work done on the box…

A: WE know that   w = F.S COSθ WHERE FORCE IS IN THE DIRECTION OF DISPLACEMENT