Consider a lawnmower of mass m which can slide across a horizontal surface with a coefficient of friction μ. In this problem the lawnmower is pushed using a massless handle, which makes an angle θ with the horizontal. Assume that Fh, the force exerted by the handle, is parallel to the handle.
Find the magnitude, Fh, of the force required to slide the lawnmower over the ground at constant speed by pushing the handle.
The solution for Fh has a singularity (that is, becomes infinitely large) at a certain angle θcritical. For any angle θ>θcritical, the expression for Fh will be negative. However, a negative applied force Fh would reverse the direction of friction acting on the lawnmower, and thus this is not a physically acceptable solution. In fact, the increased normal force at these large angles makes the force of friction too large to move the lawnmower at all.
Find an expression for tan(θcritical).
Answers: 1
Physics, 22.06.2019 19:30, isiahb123
A47.2 g block of copper whose temperature is 480 k is placed in an insulating box with a 91.8 g block of lead whose temperature is 200 k. (a) what is the equilibrium temperature of the two-block system? (b) what is the change in the internal energy of the two-block system between the initial state and the equilibrium state? (c) what is the change in the entropy of the two-block system? the heat capacities of copper and lead are 386 j/kg·k and 128 j/kg·k, respectively.
Answers: 1
Physics, 22.06.2019 22:30, nickocasamplonp6mlob
The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.
Answers: 2
Consider a lawnmower of mass m which can slide across a horizontal surface with a coefficient of fri...
Mathematics, 15.07.2019 08:20
Biology, 15.07.2019 08:20
Mathematics, 15.07.2019 08:20
Mathematics, 15.07.2019 08:20
History, 15.07.2019 08:20
History, 15.07.2019 08:20
Social Studies, 15.07.2019 08:20