Question

a block of known mass is sliding across a horizontal frictionless surface with a known speed when it suddenly encounters a rough patch. if you wanted to calculate the amount of frictional force exerted during the rough spot what would you need to measure. give two ways to do this and the equipment you would use for each way.

Answer 1

To calculate the frictional force on a sliding block, you can measure its deceleration using a motion sensor or calculate the work done by friction by measuring the stopping distance with a ruler. The block's mass and initial speed are necessary for both methods.

Step-by-step explanation:

Calculating Frictional Force on a Rough Patch

To calculate the amount of frictional force exerted on a block sliding across a rough patch, you need to measure the rate at which the block slows down over the rough area. There are two methods to do this:

1. Measure the deceleration of the block using a motion sensor or a speed radar. Equipment like a laser sensor or speed gun could provide the velocity data at various points, allowing you to calculate the deceleration assuming a constant frictional force. If we know the mass of the block, we can use Newton's second law to find the frictional force (F=ma).
2. Measure the distance over which the block comes to a stop and use the work-energy principle. Equipment such as a ruler or a measuring tape could be used to determine this distance. The work done by friction is the product of the frictional force and the distance (W=Fd), which equals the change in kinetic energy of the block. This change can be calculated knowing the initial speed and mass of the block and setting it equal to the work done by friction.

Note: In both cases, the mass of the block and its initial velocity before hitting the rough patch are essential data.